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CarlaW
01-07-2005, 08:46 PM
Ok, just did my weekly water tests and here's the story.
alk-3.14
Ca-420
Mg-1200
The Mg is a little low compared to natural sea water levels, but it is still about 3 times what the Ca level is. Do I dose a little Mg to get the level to 1300, or do I ride the tide and let it go?
I am using Oceanic salt, have been since July.
Let me know if you need any more test results, I can definitly accomodate.
Thanx in advance,

:D

WaterDogs
01-07-2005, 09:35 PM
Hi charlie,

People that have helped me always said 1250 was ideal. According Salifert test kit instructions they say don't go over 1500 for a maximum. At 1200 I personally would add and bring it up to 1250 then check it again in a week and see how much it dropped.

Dwaine

CarlaW
01-07-2005, 10:02 PM
Thanx WaterDogs, I had a hunch that was what someone was gonna tell me, let's see if anybody else has an opinion.

DonW
01-07-2005, 10:10 PM
Mg falls real slow, but I'd do a WC to bring it back up since your using Oceanic. You just dont want to have calcium problems down the road. Once it gets to low its a real pain to get it back up.

Don

CarlaW
01-07-2005, 10:15 PM
I have never measured the wc water for Mg. Maybe I'll go do that now since I just happen to have some handy!! Keep those opinions coming, they are always helpful. :)

CarlaW
01-07-2005, 10:23 PM
Well, I came up with a reading of 1470. I do a 20 gallon WC every week. Does anybody think that this will be enuf to raise my Mg without having to dose? I could own stock in Seachem if I followed their dosing calculations!!!!!! :D

DonW
01-07-2005, 10:27 PM
Charlie

It will bring it up. Save your money.

Don

CarlaW
01-07-2005, 10:29 PM
Thanx Don, I think I'll go with that. How soon after a change would you recommend testing, 1hr., 2hr. ???

WaterDogs
01-07-2005, 10:50 PM
Well, I came up with a reading of 1470. I do a 20 gallon WC every week. Does anybody think that this will be enuf to raise my Mg without having to dose? I could own stock in Seachem if I followed their dosing calculations!!!!!! :D

A 20 gallon WC isn't going to bring 475 gallons of water up to 1250.

Dwaine

CarlaW
01-07-2005, 10:56 PM
That is a good point, but right now, it comes down to a point of affordabilty. I'm kind of stuck between a rock and a hard spot. According to Seachems formula, I need to dose 150 teaspoons of their additive to get it up to 1250. There aren't 150 teaspoons in the bottle that I have!!!!!!!!!!!! Maybe a larger WC???

WaterDogs
01-07-2005, 11:04 PM
I'd say a balance of larger WC and the Mg additive. I only have 75 gallons to care for so I never thought of having to use more than the whole bottle of an additive! :D

MikeS
01-08-2005, 12:48 AM
Curious, what SG do you keep you main tank at?

MikeS

Boomer
01-08-2005, 01:37 AM
I need to dose 150 teaspoons of their additive to get it up to 1250

Or 3.3 pounds of Calcium Chloride :D

Go here

http://www.andy-hipkiss.co.uk/

Click on Physical Environment----->Chemistry---> Mag Sups

I would take WaterDogs advice but you are not that low.


Reading :D

Magnesium in Reef Aquaria
http://www.advancedaquarist.com/issues/oct2003/chem.htm

Magnesium: Calcium's little sister
http://www.aquariumfish.com/aquariumfish/detail.aspx?aid=2345

Curious, what SG do you keep you main tank at?

Me too Mike &

1. Who's Sg meter/refract, floater, swing arm

2. What temp is the tank

3. What temp is the Sg calibrated to

4. If it is a refract is it corrected for seawater's "15" units negitive error

CarlaW
01-08-2005, 07:55 AM
Specific gravity is at 1.024 with a refractometer.
Temp in tank is 78-81.
Calibrated to 78.

Boomer, thanx for the reading, assignment, a guy can always get used to Randy Holmes Farley @ 6 AM on a Saturday morning. Whew, I think I need more coffee :D .
RE., WaterDogs advice, instead of a larger change, would a few 20 gallon changes in a week along with a one time supplementation,(all I've got), help to get me to 1250, at a bare minimum?

DonW
01-08-2005, 10:10 AM
WC are easy and cheap. You dont need to do it all in one shot. Just at a faster rate than your using it. Your not that far off.

Don

WaterDogs
01-08-2005, 12:45 PM
Hi Charlie,

A 10% water change a week would be 47.5 or 50 gallons in round numbers. I would take out 50 gallons then put in the new 50g then add the whole bottle of Mg and you may be very close and able to maintain with just WC after that especially with Oceanic's high Mg level. There is a point where salt will cost just as much as the additive and sweat :D.

You could change 100gallons a week if you wanted just don't shock the system whatever you decide to do. I know an increase from 1200 to 1250 in one shot is safe.

How much will Epsom salts cost as the site Boomer recommended http://www.andy-hipkiss.co.uk/ says it can be used and I think RHF said that also.

Let us know what you decide upon?

Dwaine

Boomer
01-08-2005, 01:35 PM
charlie

Your SG it to low, what is part of your problem

1.024 -15 units = a real SG of 1.024 - .0015 = 1.0225 = 30 ppt

You are way to low on your salinity and need to get to 35 ppt. Your refract needs to read;

1.028, which with the error correction = 1.028 - .0015 = 1.0265 corrected = 35ppt NSW. Raising your salinity up to NSW will give you a 15 % increase in Mg but that Ca will also increase 15 %. Of course that would be if you were starting with all new water. I like so far WD suggestion and see what you get


With a salinity that low is a major reason your Mg is so low. Part of your problem is going to be Oceanic salt, if that is what you are using, has it usually has a very high Ca. I did not know the Mg was also high.



WD

Are you sure about that high Mg or are you mistaking it for high Ca ?

CarlaW
01-08-2005, 01:41 PM
How would you go about raising the salinity? Make my next batch of change water @ 1.030?

WaterDogs
01-08-2005, 02:01 PM
Boomer asked:
WD

Are you sure about that high Mg or are you mistaking it for high Ca ?


WD:
Not mistaking it for CA. That is mostly what I have read/heard; when I was using Oceanic salt at 1.026 on a refrac my Mg was always close to or over 1500, but my reef is lightly stocked so usage is low.

Maybe someone here could mix some batches of Oceanic and test Mg for us?

Dwaine

CarlaW
01-08-2005, 02:04 PM
My batch of oceanic tested @ 1470 as I stated earlier :D

WaterDogs
01-08-2005, 02:16 PM
Boomer,

Could you explain this "units" and "real SG" to us?



1.024 -15 units = a real SG of 1.024 - .0015 = 1.0225 = 30 ppt

You are way to low on your salinity and need to get to 35 ppt. Your refract needs to read;

1.028, which with the error correction = 1.028 - .0015 = 1.0265 corrected = 35ppt NSW. Raising your salinity up to NSW will give you a 15 % increase in Mg but that Ca will also increase 15 %. Of course that would be if you were starting with all new water. I like so far WD suggestion and see what you get

CarlaW
01-08-2005, 09:45 PM
WD,
20 gallon water change and lots of seachem ( :D ),and end result, Mg=1275. I think I should be able to maintain that level with water changes, don't you?
Thanx for your help.

Boomer
01-09-2005, 01:36 AM
WD

All refracts that you buy are calibrated to an NaCl solution. 35 ppt of NaCl is no the same thing as 35 ppt NSW. NSW has a higher refraction of light than NaCl. That off sets the refract by "15 units". I say 15 for this reason. A refract may be giving the "salinity in ppt, % solution or SG, so

Refract reading = 35 ppt - "15 units" 35 -1.5 = 33.5 ppt NSW

Refract reading = 3.5 % solution - "15 units" = 3.5 % solution - .15 =3.35 % NSW = 33.5 ppt NSW

Refract reading = 1.0265 SG - "15 " units = 1.0265 - .0015 = 1.025 = 33.5 ppt NSW

If you want to DIVE into it here is something for you to read I helped Randy collect data for;

Reef Aquarium Salinity: Homemade Calibration Standards
http://reefkeeping.com/issues/2004-06/rhf/index.htm


That is mostly what I have read/heard; when I was using Oceanic salt at 1.026 on a refract my Mg was always close to or over 1500

OK, because we know there have been many getting very high Ca almost to 500 mg / l.



Charlie

You seem to be on track :D

CarlaW
01-09-2005, 08:39 AM
Boomer, could you address raising the salinity in an existing tank? Thanx for your guys help. I don't normally like to cahnge things that quick in my tanks, but I don't see anything bad goin on, so I guess I'm alright.

WaterDogs
01-09-2005, 08:42 AM
I'm glad your problem is solved Charlie and thanks Boomer for clarifying! :)

Dwaine

CarlaW
01-09-2005, 08:45 AM
WD, ain't nothin solved yet, just cured for the moment. We'll see what happens here with the next few weeks. :eek:

WaterDogs
01-09-2005, 08:58 AM
WD, ain't nothin solved yet, just cured for the moment. We'll see what happens here with the next few weeks. :eek:
If you are dead set on only changing 20 gallons a week of water that is fine but the Mg level will go down so just adjust with an additive.

To raise SG on my 75g I take out a gallon or two off water and add the 1/2 to 1 cup salt mix and add back to the tank this will raise it I think 1 point.

Dwaine

CarlaW
01-09-2005, 09:03 AM
I was lookin at maybe changing 30, but I still think I might have to supplement. I should buy stock in the company that makes epsom salts. I like the idea about raising salinity tho, thanx.
I need to keep an eye on the Mg this week to see just what the consumption is and will be. I'll try to keep this updated!!

fishermann
01-09-2005, 10:17 AM
Charlie You can go to the drug store and get some epson salts and bring your mag up easy, just do it slowly. Mix like 2 cups with a gallon of water and check your mag level after a while with a Salifert kit. This well bring it up very easly without big water changes and then you can use the mag spplements to keep it at the proper level, but using Oceanic salt, which is what I use, You tend to have a high mag level. I was using Kent when I had the low mag problem with a level of 1090 and I brought mine up to 1350 in 4 or 5 days with epson salts which Mojo told me about since he had had the same problem. You want your parims all to be around nsw and that is 1290 for mag.

Boomer
01-09-2005, 12:51 PM
could you address raising the salinity in an existing tank?

No more than 1 actual unit / week, so it would take you 4 weeks. You are /were at 1.024 and need to get to 1.028. ie., 1.024-->1.025-->1.026--->1.027--->1.028.

This will make it easier :D

http://www.saltyzoo.com/SaltyCalcs/SalinityAdjust.php

Make sure you use the same units, as in ppt or SG

EDIT

Don't use Sg ONLY ppt in the window. You get funny answers with SG. So, at 30 ppt and you what to go to 35 ppt @ 50 gal / week WC

CarlaW
01-09-2005, 01:24 PM
Boomer, if I am following that correctly, that would mean that I wouldn't actually be doing a water change, I would just be increasing the salinity of the water I removed from the tank, and then replacing the water into the tank. Please correct me if I am wrong.

mojoreef
01-09-2005, 02:13 PM
Charlie you could do it via a more concentrated sg with the water you are adding via the wc. So you could make the WC water as concentrated as required to raise the sg a point a week.
I would not put so much worry into the Mag level being low, with that salt mix its going to be a to high problem really quick anyway.


Mike

CarlaW
01-09-2005, 02:24 PM
Ok, thanx mojo for helping out. Your solution is kinda what I was hoping. The calculator that Boomer gave me set the parameters for me. I was just a little confused, I'm old, give me a break. :D
Again, thanx all you guys for your help, it is much appreciated :) .

fishermann
01-09-2005, 03:38 PM
I emailed oceanic a six or so weeks ago asking them about these reported high Mag readings people have been having with their salt. I have not had an issue using it and infact I like the salt and have been using it for about 6 mos. now and like the sps growth I'm getting since switching and it has been alot easier to keep my parims right. I run my sg at 1.025 with a refractometer and my mag levels stay dead on 1290. Anyway their answer the next day was that their product is made to have proper mag levels at a SG of 1.025 and that running the SG higher well raise the mag levels. I raised my SG to 10.26 in my softie tank and took a test one week later and the mag levels had went up to 1350 and then the next week to 1390. I since lowered it back down to 1.025 and things are almost back to normal. So I believe that they are correct and that you need to keep your SG at 1.024-1.025. Charlie you were at 1.024 which with a mag level of 1250 would be about right according to them. I have no mag issues with the salt at 1.025. Thanks

cwcross
01-09-2005, 06:16 PM
Edited...for a mistake...C

mojoreef
01-09-2005, 06:17 PM
John if charlie was measuring at 1.024 using a refractometer his salinity after compensation would be 1.023 (little less actually) This woould mean that his salinity was 14% lower then NSW at 35ppt or 1.027. Thus all the elements that make up the water would also be 14% lower if they were in balance. So at the salinity of 1.023 his mag level should be 1109 (1290 - 14%). If his mag level right now is 1275 then it is around 13% higher then it should be, so 1275 -1109= 165 parts to much, if the salinity remains consistant that means a 165 parts of something else needs to come out of solution, then add the cal being to high and its even more, alk is definately one of the elements that is being effected.


Mike

mojoreef
01-09-2005, 06:19 PM
Sorry Collin I posted at the same time


MIke

cwcross
01-09-2005, 06:23 PM
No problems mike. I accidentally failed to read the entire thread and based a response only after reading the first page... Here is my response...however, it apprears that a useful adjustment was discovered for the tank...however, I will post my reply to take with a grain of salt...Collin

Previous edited post:

1250 for Mg may be an ideal target. However, I suggest that the difference between 1200 and 1250 ppm of Mg may be well within the error of the test kit. Reef kit titrations are notoriously inaccurate and there are fundamental reasons why this is true.

Think of it this way. 50/1250=0.04 or 4%. This means you are only 4% away from your target. This is a minor difference. You might consider waiting until you are more like 10-15% away from your target (or maybe even 20-25). When dealing with target levels in the aquarium, these are not usually critical values. Just targets to keep your eye on over time. If things start to get way out of whack, or you are actually having problems, I would suggest action. I don't suggest trying to keep levels pegged at thier optimums all the time though. Just some thoughts...Sincerely...Collin

Boomer
01-10-2005, 01:27 PM
Charlie

as Mojo said Charlie you could do it via a more concentrated sg with the water you are adding via the wc. So you could make the WC water as concentrated as required to raise the sg a point a week

The calculator does this for you. You could raise the salinity 1 point / wk with 1 gal of water. Yes you could remove tank water and increase its SG, IMHO I would use new water.

In the cal window type in

475 gals = (net water)
30 ppt = what you have
35 ptt = where you want to go
1 ppt= change / week
1 gal= size of gal WC. or 5 gal., 10 gal etc.


For a 1 gal change = 1.46 sg / 505 ppt

for a 10 gal change = 1.059 sg / 77.5 ppt

for 50 qal = 1.03 sg / 39.5 ppt

DonW
01-10-2005, 01:36 PM
What would the draw back be to just adding salt to your evap top off?
Not to steal the thread, but what is the formula used by calculators for ca/alk balance?

Don

CarlaW
01-10-2005, 07:23 PM
Boomer, got you covered on this! Already printed it up for 30 gallon water changes over the next month or so.
Thanx.

cwcross
01-10-2005, 07:24 PM
What would the draw back be to just adding salt to your evap top off?
Not to steal the thread, but what is the formula used by calculators for ca/alk balance?

Don


Don,

I do not believe it is really a "formula" per say. Notice that the balanced "line" is indeed a straight line. This means it is a simple ratio between Calcium and Alkalinity. The "balanced" part of it comes from the ratio found to be present in natural sea water. Notice how the line cuts dead center throught the value of natural sea water. That ratio, in terms of the molar ratio between Ca and total Alk, is just maintained through out the line. It is basically natures magic number. The ratio of Ca and Alk is not stoichiometric when related to Calcium Carbonate. That is to say that there is a LOT more Ca than Alk. Here is a link that explains things in more detail:

http://www.reefkeeping.com/issues/2002-04/rhf/feature/

cwcross
01-10-2005, 07:26 PM
What would the draw back be to just adding salt to your evap top off?
Not to steal the thread, but what is the formula used by calculators for ca/alk balance?

Don

No drawback. In fact you could just pour it directly into your sump if you wanted to in dry form. May not be the most elegant solution but it would work. Just be sure to do it over a few days or weeks so you don't raise salinity too far too fast. Some animals are more sensitive to changes in salinity than others.....C

Illusion
01-10-2005, 07:53 PM
I have Tested my Oceanic at 36ppt and it comes out to 500ppm Ca and 1500ppm Mg

I emailed Oceanic today and this is the Response that I got back from them

"At a specific gravity of 1.021 – 1.023 Oceanic sea salt yields calcium concentrations of 420 – 480 ppm which are comparable to natural sea water.
Some reef tank aquarists prefer to maintain their tanks at a specific gravity of 1.025 or greater. With Oceanic salt, this high specific gravity results in calcium levels that can exceed 550 ppm which can disturb the delicate carbonate/bicarbonate equilibrium causing transient pH fluctuations. For reef tanks it is recommended that Oceanic salt be used at 1.024 specific gravity which should yield high calcium and magnesium levels without causing hardness and pH imbalance.

We have talked with the scientist who formulated our salt about this issue. He does not feel the formulation should be changed. Here are some suggestions that were given from him for aquarist who feel it is necessary to run their tanks and higher specific gravity.


1) Mix Oceanic salt to sg 1.023. To this slowly add and completely dissolve solid analytical reagent grade sodium chloride to desired sg. This procedure will increase sg without effecting calcium and magnesium levels.

2) Mix Oceanic salt to sg 1.023 – 1.025. Before adding to tank, treat with dKh hardness buffer to attain dKh of 5-7. Add gradually to tank after solution has equilibrated. "

HTH<
James

Boomer
01-11-2005, 04:36 AM
At a specific gravity of 1.021 – 1.023 Oceanic sea salt yields calcium concentrations of 420 – 480 ppm which are comparable to natural sea water


They are lost in the fog. SG has been a very complicated subject for many even though it is easy. NSW at the these SG levels yes, if the temperature calibration point of the hydrometer is 60 F. And I am assuming that they are using a lab grade SG meter, calibrated to 60 F. Thus, these given Sg @ 1.023 = 34.4 ppt if the tank temp is 82 F. Most of the floating hydrometers, we use, are calibrated to 75 F or 77 F, which gives a 1.023 @ 77 F of 30.7 ppt. I do not know of a coral reef that has a salinity that low. And or are they confused, like many, that SG they gave is not SG but Density. SG and Density are NOT the same thing. In seawater chemistry SG is not used, density is, and often unknowing authors just change the word Density to SG....that is incorrect. As temp rises SG and density move apart. At max density of seawater they are equal but has the temp rises, say to 82 F there is a "4 point" difference.


When ever ANYONE gives an SG value it needs to state some things;


Is it a
1. Hydrometer, what kind, floater, swing arm, etc. and calibrated to what temp.

2. Refract, is it corrected for by the "15 unit " error.

3. Temp of water being tested.

4. Do these "meters" have ATC


With out these these values they gave or any one gives are meaningless IMHO

It is not up for debate, their salt is to high in Ca and Mg

DonW
01-11-2005, 04:32 PM
I'm a bit slow. If I calibrate my atc refractomter with the solution temp at 60 degrees. I then mix water to 35ppt@80 degrees according to refractometer. What is it in sg and ppt in reality.

Thanks
Don

Boomer
01-11-2005, 04:59 PM
First, what are you calibrating it to ? Calibrating it to fresh water really isn't calibrating it. Calibrating on any thing should be some where near the value you are trying to reach. If you set it to freshwater at 0 ppt then you are about at 33.5 ppt the "15 unit" rule ( your 35 ppt - 1.5 = 33.5). You want to get near 35 ppt, so the reading should be 35 (NSW) + 1.5 = 36.5 ( what the refract should read to = NSW at 35 ppt. The ATC corrects for temp automatically, so tank temp is OK, not need to go down to 60 F. You will usually get the best or more assured results at 77 F, even with ATC.

mojoreef
01-11-2005, 06:35 PM
It is not up for debate, their salt is to high in Ca and Mg
No kiddin thats the second reply I have seen from them with that kind of reasoning. Its a shame the salt mixes very well and seem ok in the other catagories, but with the mag and cal at those levels its pretty much unusable.

Mike

Boomer
01-11-2005, 06:53 PM
I guess Mike, Randy, who tested some, doesn't know what he is doing :lol:

and seem ok in the other catagories

There have been a number of low alk Mojo

mojoreef
01-11-2005, 08:32 PM
Well that would be a direct result of the mag and cal levels no??

MIke

Illusion
01-11-2005, 11:07 PM
My alk doesnt seem that Low.. It mixes up at

500 Ca
1500 Mg
6-7dkh
7.9 - 8.0 pH

the good thing is the buckets seem really consistent with each other.. When Mixing at a lower salinity like they say it seems to be the perfect salt.. Someone Mentioned Water Softning salt is the Same solt that can be Used for tanks? Is this true? Can I mix my salt at like 1.022 and raise with the Water softner salt to 1.026 like Oceanic says? Is there any danger in doing this? I was close to picking up some IO today to balance the 2 out..

James

Stircrazy
01-11-2005, 11:37 PM
1. Who's Sg meter/refract, floater, swing arm

2. What temp is the tank

3. What temp is the Sg calibrated to



Boomer, is there a known deviation for different makes of swing arm testers?

I use the Coralife deepsix myself but if there was a known deviation in this brand it would be good to know.

Steve

Illusion
01-11-2005, 11:40 PM
Boomer, is there a known deviation for different makes of swing arm testers?

I use the Coralife deepsix myself but if there was a known deviation in this brand it would be good to know.

Steve
__________________

From what I have found with the Deep six is it was about .003 off from all my testing of them... Only tried 3 different ones from my Refract but they were all .003 off roughly... If your at .027 then you are really at .030 I would suggest .024 being safe for the DeepSix..

James

mojoreef
01-12-2005, 12:16 AM
James your parameters are way off for alk. For NSW at 35ppt your calcium should be 415, mag=1290 and alk around 7.5dkh. If you are mixing the salt at 35ppt and getting 500 for cal and 1500 for mag its telling you that you that your calcium is over 20% to much and your mag is about 15% to high, while at the same time your alk is around 10% low. Just wacky.

Here is the way to look at it. if your SW is at 1.027 the calcium level should be 415 and mag 1290. If you drop your salinity to 1.026 you have reduced it 3.5% so all levels of elements would drop by that same 3.5%, so cal=400 and mag=1244.
So if thier saying you should mix the salt up at 1.023 then if ll the elements in the SW went in balanced the cal should be 356 and your mag would equal 1109. Make sence??
So what they are really saying is that they put to much mag and cal in the formula and they want you to mix it at a lower salinity and then buffer it up with a salt that does not have cal or mag in it, Or take thier mix with the high cal and mag and try to beat them down by buffering the heck out of it.

The right answer would be oooppps we will start making it proper so you can just mix it and put it in your tank.

Mike

Boomer
01-12-2005, 01:00 AM
Mike

Well that would be a direct result of the mag and cal levels no??

No, you just add more MgCl and CaCl with little baking soda added

Boomer
01-12-2005, 01:12 AM
Jim

I don't' like the Deep Six. Every one I've seen is way off and may others have tested them and finding them way off. .003 is way off :) It should be no more off than .001 and max at .002.

[b]Boomer, is there a known deviation for different makes of swing arm testers?

No, generally. It depends, if there are made of thermal expansion plastic, which is like automatic temp compensation. The only swing arm I trust is the SeaTest, which I now does this and is CARED for properly. On the avg, the SeaTest's we have played with, are 1 ppt to low. Mine is right on the nuts :D

Illusion
01-12-2005, 02:34 AM
Hey Mike I hear ya there.. That is by far not the Answer that I wanted from them but What more can I do... I have my own Ideas but I would like to stay here with my Family LOL... The Ca I am not too worried about I got it down pretty low in the tank.. about Ca 450 and Alk 8.3ish Dkh... My Mg is still 1500... Thats what my goal is I want the Mg lower... I am fairly confident that if it was atleast 1400 that my pH issues in my tank would be corrected as well. not really an issue 7.9-8.2 but I dont like that... I am looking for an Easy way to even just drop the Mg in the WC bucket so that when i do my water changes it will lower it slowly... any suggestions without changing salt or lowering the Sg lower than 35ppt... I mean Everything in my tank loves the salt and I am getting mass growth and no algae.. Just that high Mg bothers me..

James

mojoreef
01-12-2005, 08:58 AM
Well that would be a direct result of the mag and cal levels no??
No, you just add more MgCl and CaCl with little baking soda added

Ok I think we are on different paths here, you lost me, lol

MIke

mojoreef
01-12-2005, 09:05 AM
James I dont really know a way to lower the mag in the bucket, maybe the addition of alk buffer will percipatate it out, but that more of a Collin, or Boomer question.
Watch the calcium level though, remember calcium is a waste product for corals and it inhibits the coral tissue growth. To rid itself of the calcium the coral has to use energy, the higher the level the harder your making the coral work, and the more energy it has to divert from other needed activities.


MIke

cwcross
01-12-2005, 09:58 AM
I'm not clear why you are worried about slightly high Mg levels. I do not think the Mg is the cause of your pH problem. Even if they were, the difference between 1300 and 1500 would not cause such a significant deviation in pH. I certainly would not suggest trying to precipitate out your Mg. It would likely co-precipitate with something else and runs the risk of causing more problems than it is worth. Withough changing salts or doing only very infrequent water changes and just letting the Mg drop naturally, I'm not sure there is a good way to lower it after the fact. I don't think it is even worth worrying about though. If you are happy with your salt. Just stick with it and balance it as best you can. Adding pure NaCl to change the ratio of bulk salt to Mg levels is about the only way that is reasonable. If it is a problem...consider changing salts. This is a know deficiency of the brand you are using.

Sincerely...Collin




James I dont really know a way to lower the mag in the bucket, maybe the addition of alk buffer will percipatate it out, but that more of a Collin, or Boomer question.
Watch the calcium level though, remember calcium is a waste product for corals and it inhibits the coral tissue growth. To rid itself of the calcium the coral has to use energy, the higher the level the harder your making the coral work, and the more energy it has to divert from other needed activities.


MIke

mojoreef
01-12-2005, 10:21 AM
Collin does Magnesium not take Alk out of solution?? Wouldnt a mag level that is about 15-20% higher then normal have a profound effect on alk, which in turn deplete your Ph bufering??


Mike

cwcross
01-12-2005, 11:29 AM
Collin does Magnesium not take Alk out of solution?? Wouldnt a mag level that is about 15-20% higher then normal have a profound effect on alk, which in turn deplete your Ph bufering??


Mike

If you add Magnesium Carbonate buffers then yes Alk will increase. However, magnesium getting out of balance over time will not affect measured alk.

Magnesium and Alk measured in an equilibrated tank are independant...unless you have problems with precipitating Lime. In this case Magnesium carbonate would co-precipitate with calcium carbonate and could lead to a reduction in Alk. However, this indicates a problem other than Mg levels (unless they are very low). As long as everything is staying in solution, the Mg and CO3/HCO3 will exist as stabilized but independant ions and the alk will be available for buffering via acid-base reactions.

If you start to see lime precipitating, then it will contribute to the loss of Alk. Otherwise, no it should not according to my thinking.

Sincerely...Collin

Boomer
01-12-2005, 12:01 PM
Mike

There have been a number of low alk Mojo

Well that would be a direct result of the mag and cal levels no??

Ok I think we are on different paths here, you lost me, lol

Ok I'll give you a compass to find your way back :D

It sounds like you are saying oceanic has high Mg and Ca, thus the reason for low Ak. My answer is no, all a salt manufacture has to do is add more MgCl and CaCl to the mix, with little buffer ( as in baking soda), if they added more buffer the Alk would get higher. They would not want to add to much buffer or the Ca and Mg would just precip out of solution.

Your reading assignment :D

Magnesium in Reef Aquaria
http://www.advancedaquarist.com/issues/oct2003/chem.htm

I know of no safe way to remove Mg, I would leave it alone as Collin has suggested or do WC. Mg can have a toxic effects but only when it gets much, much higher.

mojoreef
01-12-2005, 12:43 PM
Ok I will bite, lol Chemistry is my friend...chemistry is my friend :p

here is my limited understanding. Magnesium limits the formation of calcium carbonate crystals, to the point at which this formation can even stop, if that is the case then calcium carbonate is not forming, which is a problem for corals as they need the carbonate to pull the calium out of thier cell structure. Now also with the carbonate level being low to start with even at natural mag levels calcium carbonate percipatation will be significantly.
So with calcium ions binding to the carbonate and magnesium ions binding to the carbonate ion how is it supposed to do it job as a buffer or in percipatation? Also doesnt mag poison the seed surface so calcium carbonate wont precipatate?? doesnt that pose a large problem for a corals calcification process??

Ok I am tied to the whipping post boys...have at me :badgrin:

Mike

Boomer
01-12-2005, 01:48 PM
I just sharpened my whip ;)

Magnesium limits the formation of calcium carbonate crystals, to the point at which this formation can even stop......if that is the case then calcium carbonate is not forming, which is a problem for corals

This has nothing to do with corals. You are comparing apples and oranges. It is what happens on bare fresh surfaces of carbonate minerals ( gravels), which means high magnesium carbonates are not being formed on the surfaces of fresh carbonate minerals, which means the Mg, Ca and Alk are staying in solution, making it available for corals. Dolomitic gravels will have the highest effect of high Mg calcite precip out on the surface of the dolomite mineral. Pure Calcite will be the least. However, pure dolomite is less soluble than pure calcite. This is may/can be a temporary thing. These surface poisons are very soluble and can/may go back into solution easy. Precip can also happen on heater, glass etc, which is a little different chemistry. Coral biology and their formation of Calcium carbonate is another beast :D You are comparing what happens to a bare rock surface to what happens inside a live coral, not the same thing. In a reef tank or even in the ocean this doesn't' happen much, as the gravels get a bacterial surface coating and precip will be nil, if at all. In a new tank it would/may be a temporary thing.



You did not read your homework assignment now did you :(

How does magnesium interfere with precipitation of CaCO3? The primary way involves magnesium poisoning the surface of growing CaCO3 crystals, slowing the precipitation. It can, in fact, be slowed to the point where it simply does not happen at rates problematic to an aquarist. In the following discussion it is important to remember that, other things being equal, alkalinity is a good indicator of the concentration of carbonate. So higher alkalinity equates to higher carbonate.

In short, while magnesium carbonate is not supersaturated in seawater (or in typical reef aquaria), and will not precipitate on its own, magnesium is attracted to calcium carbonate surfaces where the carbonate ions are already held in place by the calcium ions. With the carbonate ions held in place, magnesium finds this an attractive place to bind.

After a short time in seawater, a virgin calcium carbonate surface quickly attains a thin coating of Mg/CaCO3 (magnesian calcite) as magnesium pushes its way into and onto the crystal surface. Eventually, the surface contains a substantial amount of magnesium. The extent to which this happens depends on the underlying mineral, and is apparently much more extensive on calcite than aragonite. It also depends upon the relative amounts of calcium and magnesium in the water. Regardless, a new type of material is formed that contains both calcium and magnesium.

This new mineral surface containing both calcium and magnesium is not a good nucleating site for precipitation of additional calcium carbonate (as aragonite or calcite), and precipitation of additional CaCO3 slows down substantially.


In Captive Seawater Fishes there is an extensive discussion of the impact of magnesium on the calcium/carbonate system, including a set of data that indicates the magnitude of the impact that magnesium can have.25 In this experiment, batches of artificial seawater were made up with varying magnesium and carbonate levels. The scientists then measured how long it took for calcium carbonate to precipitate from each solution. Not surprisingly, the higher the carbonate was raised, the more rapid was the precipitation of calcium carbonate.

More interestingly, the magnesium levels were found to have a very large impact on the rate of precipitation. In batches with no magnesium, and at natural calcium and elevated carbonate levels, calcium carbonate was found to precipitate in minutes. With a natural seawater level of magnesium added to that mix, the precipitation was delayed to 13 to 20 hours. With double the natural magnesium concentration, the precipitation was delayed to 22 to 29 hours.

Even more strikingly, at a lower level of carbonate (closer to that of natural seawater and probably similar to that in many reef aquaria), precipitation was delayed from a few minutes in the absence of magnesium to 750 hours in the presence of natural levels of magnesium. Consequently, magnesium has a big impact on the rate of precipitation of calcium carbonate (a fact that has been confirmed by many researchers).

But what does that have to do with a reef aquarium? One situation in which calcium carbonate can precipitate involves adding calcium carbonate seed crystals of some type to the aquarium. For example, by adding calcium carbonate sand or one of the calcium carbonate supplements like Aragamight or Kent’s Liquid Reactor.26

A second situation where solid CaCO3 forms is when abiotic precipitation initiates in the aquarium.24 This precipitation happens when supersaturation is pushed to unusually high levels (either in the tank as a whole, or in localized regions). This rise in supersaturation can be caused by a rise in pH (which increases the amount of carbonate present by converting bicarbonate into carbonate), a rise in temperature (as on a heater or pump impeller; the temperature rise decreases the solubility of calcium carbonate and also converts bicarbonate into carbonate), or more directly by a rise in either calcium or carbonate.24

After the solid calcium carbonate has appeared in the system by whatever means, precipitation of CaCO3 will begin immediately. What processes inhibit continued precipitation of CaCO3 onto a growing crystal? The main thing happening in normal seawater is likely the impact of magnesium (though phosphate and organics may play an important role in some aquaria).24 This is the point that magnesium gets onto the growing surface of the crystal, essentially poisoning it for further precipitation of calcium carbonate. Since magnesium can reduce the likelihood or extent of calcium carbonate precipitation in this fashion, it thus acts to make it easier to maintain high levels of calcium and alkalinity.

Illusion
01-12-2005, 01:59 PM
Ok I am tied to the whipping post boys...have at me

LMAO too funny..

As for the Salt question I tried to Precip the Mg out of a 5g bucket last night.. Well I dont think that worked.. I think I caused major issues in the bucket LOL... Still cloudy 12hrs later... I think I might have preciptated everything out of there LOL...

I did email Oceanpure about testing some of their salt and what their "Target" levels are..
The basic levels on:
Ca. 400 to 420
Mg. 1100 to 1200
KH 7.5 to 8.2
PH 8.2 to 8.3

The pro series:
Ca. 430 to 450
Mg.1350 to 1450
KH 8 to 9
PH 8.2 to 8.4

Thats what I was told from them... I am hoping they are sending me a sample to test it as well..

James

cwcross
01-12-2005, 03:24 PM
I just sharpened my whip ;)

[/b]

Ok, you have saved me some serious typing :-) I'll bet you say the same thing I would...let me read...Collin

cwcross
01-12-2005, 03:28 PM
LMAO too funny..

As for the Salt question I tried to Precip the Mg out of a 5g bucket last night.. Well I dont think that worked.. I think I caused major issues in the bucket LOL... Still cloudy 12hrs later... I think I might have preciptated everything out of there LOL...

I did email Oceanpure about testing some of their salt and what their "Target" levels are..
The basic levels on:
Ca. 400 to 420
Mg. 1100 to 1200
KH 7.5 to 8.2
PH 8.2 to 8.3

The pro series:
Ca. 430 to 450
Mg.1350 to 1450
KH 8 to 9
PH 8.2 to 8.4

Thats what I was told from them... I am hoping they are sending me a sample to test it as well..

James


Hey, its easy to precipitate magnesium. Just use concentrated NaOH and raise the pH to about 12. You'll drop out the Mg all right! :-)

Illusion
01-12-2005, 03:30 PM
Well I went to test my 5g test bucket... Pulled it from the tank and threw a PH in there for circulation... I added 6tsp of Baking soda and 1tsp of Washing soda... Whoops overshot.. Good thing Mg preciped out of the water.. from 1500 last night to 1290 this Am LOL.. Water is cloudy.. Alk is thru the roof.. LOL 51.2Dkh.. I wasnt even going to waste the kit to test the Ca... pH was 8.2 in the morning though... LOL.. More than likely its the alk that boosted the pH up though Correct??

James

cwcross
01-12-2005, 03:39 PM
Yea, the addition of BS and WS (which are bases) shot your pH up to around 12. At this point some Mg salts will drop out. Plus I don't even think BS and WS are that soluble. They are probably sitting on the bottom of the bucket too. Then overnight CO2 dissolved into your water and formed carbonic acid. Then the carb/bicarb and carb-acid all equilibrated and precipitated and the pH dropped closer to the natural solubility and pH of the mixture.

Seriously though. I think you are worried too much of this Mg thing. It doesn't hurt anything to be somewhat off target. Even way off target isn't bad as long as everything is staying in solution. Mg is largely a spectator...not a major player. It mainly just moderates CaCO3 solubility. It does get used some but mainly just because it is laying around.

I wouldn't worry about it if it was me. Your levels are well withing the green range...Collin



Well I went to test my 5g test bucket... Pulled it from the tank and threw a PH in there for circulation... I added 6tsp of Baking soda and 1tsp of Washing soda... Whoops overshot.. Good thing Mg preciped out of the water.. from 1500 last night to 1290 this Am LOL.. Water is cloudy.. Alk is thru the roof.. LOL 51.2Dkh.. I wasnt even going to waste the kit to test the Ca... pH was 8.2 in the morning though... LOL.. More than likely its the alk that boosted the pH up though Correct??

James

Illusion
01-12-2005, 03:47 PM
Sounds good... I am going to play around with some Salt in a 5g bucket and see if I cant figure some things out... From this time Fwd I am boycotting water changes... only going to add water removed from Monthly frag trades... Just going to have to monitor nitrates and Po4 a little closer... Water changes are Evil LOL... Ca and Alk are right in line so I will just make sure to keep those there... If I boycot water changes anything else I should keep a close watch on? Using ARM media if that helps for the reactor..

James

Boomer
01-12-2005, 03:50 PM
Hey Collin, you took away my thunder. I was going to post that.....I was waiting, I guess I waited to long :lol:. I usaully don't give all the info in one post, I like to bait people ;)Hey, its easy to precipitate magnesium. Just use concentrated NaOH and raise the pH to about 12. You'll drop out the Mg all right! :-) or Ca(OH)2,, as you will end up with Mg(OH)2). When you dump kalk in seawater that is the cloud you usually see.

At this point some Mg salts will drop out.


Yes and Ca also

Plus I don't even think BS and WS are that soluble. They are probably sitting on the bottom of the bucket too.


I'll bet on it they will :D

NaH2O
01-12-2005, 03:53 PM
Wow, great thread! I have to go back and read everyone's reading assignments because I thought I had an understanding and now feel confused (Mike, you better read your assignment....Boomer made it easy for you). When I used Oceanic my Mg was 1525 at corrected salinity of 35 using ATC refract (I'd have to look back at my notes....but my Ca was well over 500). I thought that was what caused the alk to be low. So far what I am understanding from the thread is the high Magnesium isn't that big of a concern. Off for the reading assignments....

Boomer
01-12-2005, 04:01 PM
Just so you know Nikki, Ca @ 400 and Mg @ 1300 really isn't a balance issue. That is just the level in seawater, meaning 1300 is not necessarily the ideal level.

Boomer
01-12-2005, 04:18 PM
I forgot to add to this

However, pure dolomite is less soluble than pure calcite

But, such Dolomites with Hi-Mg Calcites on the surface will go into solution before such poisons on Calcite will, as Dolomite has a greater affinity for Hi-Mg Calcites than Pure Calcite, thus in the long run, the Dolomite is a better "buffer material", but once those nasty bacteria sit in it makes no difference.....

mojoreef
01-12-2005, 06:44 PM
Ok I didnt get the full monti so I will call that a win!! :p I must be crazy sitting here in the house of chemistry.


It is what happens on bare fresh surfaces of carbonate minerals ( gravels), which means high magnesium carbonates are not being formed on the surfaces of fresh carbonate minerals, which means the Mg, Ca and Alk are staying in solution, making it available for corals.
Ok so what is the corals skeliton??

Coral biology and their formation of Calcium carbonate is another beast You are comparing what happens to a bare rock surface to what happens inside a live coral, not the same thing.
But I want to play with the oranges to!!,lol :p

In short, while magnesium carbonate is not supersaturated in seawater (or in typical reef aquaria), and will not precipitate on its own, magnesium is attracted to calcium carbonate surfaces where the carbonate ions are already held in place by the calcium ions. With the carbonate ions held in place, magnesium finds this an attractive place to bind. Ok so what does that mean. If you have an 1500 to start with and you continue to do Wc's are you not going to reach a point of saturation?

Consequently, magnesium has a big impact on the rate of precipitation of calcium carbonate
Ok so in an orange world say??


Ok so whip away

MIke

mojoreef
01-12-2005, 08:35 PM
Ohhh looky looky all the chemists have gone to bed...time to play....lol


Mike

cwcross
01-12-2005, 09:03 PM
Ok so what is the corals skeliton??

Yes, a coral skelaton is calcium carbonate with some magnesium and strontium mixed in.


But I want to play with the oranges to!!,lol :p
Ok so what does that mean. If you have an 1500 to start with and you continue to do Wc's are you not going to reach a point of saturation?

What Boomer is saying is that the corals don't "precipitate" lime. Precipitation is a solubility phenomenon arising from solution phase thermodynamics. Corals "deposit" lime. Although this is chemistry as well, it is moderated by biochemistry. Lots of strange things can happen in cells. In solution, an ion will always flow from local regions of high concentration to areas of low concentration. This is called a "concentration gradient". Ions in solution will always flux down a concentration gradient. In a cell, the cellular mechanisms can actually cause ions to be pumped uphill, or against the gradient. Precipitation is a passive sort of thing. Deposition is a more active phenomena. The coral is basically able to regulate the local concentrations of the ions it deals with (to some extent) via its cellular mechanisms. This is a fancy way of saying its like "apples to oranges".

Also, repeated water changes would not cause magnesium to cycle up. In this case the tank level will always be less than or equal to that of the salt water you perform changes with, all other things being equal. Now if you put salt water into your fresh water top off, that would cycle the ions up.


Ok so in an orange world say??

Make orange juice!


MIke

Night...C

Boomer
01-13-2005, 05:41 AM
Collin, I have figured it out. Mikey does not have live corals in his tank he has those dead bleached ones, so now you can see why he is concerned and thus would be correct in that regard :D Those dead corals would produce an awful lot of fresh carbonate surface areas, that would lower the Ca, Mg and ALk

mojoreef
01-13-2005, 10:31 AM
Ok I will stay out of the orange world. lol

So serious question. Wouldnt the levels of 1500 and 500 make the whole balancing act problematic?? If a person wanted to run their parameters at NSW levels , say at 415 cal, 1290 magnesium and 7-8 dkh what do you do with this salt to make it work??

MIke

fishermann
01-13-2005, 11:06 AM
Mike You guys are giving me a headache LOL , but can't you run the sg at a lower level like Oceanic says, that is what i'm doing and my parims are pretty normal and the corals are growing good and look great with this salt.

DisturbedReefer
01-13-2005, 01:01 PM
I'm using a pinpoint salinity monitor, does this have to be corrected like the refractor or is it correct?

cwcross
01-13-2005, 03:08 PM
Collin, I have figured it out. Mikey does not have live corals in his tank he has those dead bleached ones, so now you can see why he is concerned and thus would be correct in that regard :D Those dead corals would produce an awful lot of fresh carbonate surface areas, that would lower the Ca, Mg and ALk

How about those plastic ones you can buy? I thought I saw pictures of those in his tank too!

In fact, I think plastic corals are the way to go. Then I won't even have to worry about my paramenters. :D

regards...Collin

cwcross
01-13-2005, 03:21 PM
Ok I will stay out of the orange world. lol

So serious question. Wouldnt the levels of 1500 and 500 make the whole balancing act problematic?? If a person wanted to run their parameters at NSW levels , say at 415 cal, 1290 magnesium and 7-8 dkh what do you do with this salt to make it work??

MIke

Well, I don't think it is really that critical. Test kits aren't very accurate anyway. Mg of 1290 or 1500...no difference really. Alk 7-8..same diff. Same with them all. I haven't even checked my ca or alk in 2 months. I just throw some Kalk in there now and then. I know approximately what my demand is so I throw it in near that rate. Maybe I am too loose and I plan on checking this week. However, my corals are growing just fine. In fact I have an open brain (sympafelia sp?) that is a beautiful pink green. It was in terrible shape when I got it. I put it in my tank about 3 months ago. It languished for a while and is now re-growing tissue to cover the exposed skeleton. Making a nice comback. But I thought I might lose it after all at first. I got it dirt cheap.

I'm not suggesting people neglect their tanks. Just suggesting that being pinpoint accurate is not really necessary.

However, if one wanted to use the salt on the table, what to do is to mix it to whatever specific gravity led to Ca and Alk and Mg levels you want. Then add pure NaCl to raise the salinity to whereever you want it. Same with any parameters. This can be generalized to say that one could mix the salt until the first parameter maxed out to the desired level. At this point all the other parameters would be low. Then each one that was too low could be raised until it came into balance by using pure chemicals. Once everything was balanced...if salinity was still to low...make it up with NaCl. Just seems like a lot of work. There are salts out there that have the proper balance. However, we won't get into that.

I feel guilty now. I need to run home and run some reef tests...Collin

cwcross
01-13-2005, 03:25 PM
I'm using a pinpoint salinity monitor, does this have to be corrected like the refractor or is it correct?

Don't know what a pinpoint is. I'll defer to boomer or someone else here...sorry...Collin

NaH2O
01-13-2005, 03:56 PM
Collin, I believe it is a conductivity probe (?). It measures in mS, and I believe it comes with a calibration solution to 53 mS, but I'm not sure what that solution is. Did I confuse you more?

fishermann
01-13-2005, 04:12 PM
Collin without getting into a big debate on salts and such, If it doesn't bother you what salt do you use?

cwcross
01-13-2005, 04:14 PM
Collin, I believe it is a conductivity probe (?). It measures in mS, and I believe it comes with a calibration solution to 53 mS, but I'm not sure what that solution is. Did I confuse you more?


Well, this won't be perfectly accurate either then. Conductivity is based upon concentration of ions.

If we consider a set of different pure salts at equi-molar concentrations and compare them, then each salt will have a slightly different conductivity due to differing ionic mobilities. For instance, potassium iodide (KI) will have less conductivity than potassium Chloride (KCl) at the same molar concentration. This is basically because a large ion (I-) travels more slowly through water than a small ion (Cl-) due to its larger hydrodynamic radius and associated viscous drag.

The moral of this is unless you calibrate on a solution with the same ratio and groups of salts, then you will not be perfectly calibrated in seawater.

Also, concentration is dependent on temperature. Concentration has units of mass/volume. When temperature changes...volume changes and so concentration also changes. Thus the instrument should be adjusted for temperature.

How large are these effects? I don't know exactly. I would guess the conductivity effect is quite small if the calibrant solution is designed for sea water. Temperature effects will be small fairly small to but might be a little larger.

However, in the vain of my last post on this thread. I wouldn't worry about it. Maybe Boomer has some specific details to give an adjustment factor. However, animals are much more sensitive to changes in salinity etc. than to the specific salinity. As long as you keep your salinity stable and near the ideal range, I wouldn't worry.

Sincerely...Collin

cwcross
01-13-2005, 04:21 PM
Collin without getting into a big debate on salts and such, If it doesn't bother you what salt do you use?

I PM'd you...C

mojoreef
01-13-2005, 06:09 PM
LOL Collin what salt do you use????? :p No big deal saying it here my friend, just as long as you know who stays hidden ;)

Ok in a chemistry world I can see where mag being high might not have an impact but it does in a biological world. Also from a chemistry stand point if you have a calcium rate at or over 500, that is going to make alkalinity tough to raise up know? especially with magnesium on its side. Then if you take that to the biological side of the game with corals it can become a big problem with calcification??


Mike

cwcross
01-13-2005, 06:22 PM
Ok in a chemistry world I can see where mag being high might not have an impact but it does in a biological world. Also from a chemistry stand point if you have a calcium rate at or over 500, that is going to make alkalinity tough to raise up know? especially with magnesium on its side. Then if you take that to the biological side of the game with corals it can become a big problem with calcification??


Mike

Understood Mike,

I do not mean it does not have an impact. I just mean it is not critical in some cases. Corals will grow over a wide range of most parameters. They may grow best at some cerain set of parameters. They may grow worse at others (or even have negative growth). I just don't see it as critical to try and maintain values too precisely. Certainly if things get too far out of whack, it is never good. Some animals are certainly more sensitive to differences in one thing than another, while another may not care at all about that one but be very sensitive to something else. Even in the ocean, mineral species both fluctuate and also vary widely from place to place. What is typically quoted are "average values"...like 35 ppt salinity.

Things certainly need to be kept in specific ranges and each individual species of mineral has interdependencies with many others, such as Mag and Ca solubilities. However, allowing things to vary slowly over reasonable ranges, when considering the whole picture, just doesn't seem to have a large impact on my tank.

Just my opinion though...Collin

mojoreef
01-13-2005, 06:38 PM
I hear ya Collin, I also dont think folks need to be so critical. I must admit I did think mag had a chemical impact on alk, my bad. One thing I dont like to see in reef tanks is high levels of calcium, it makes the coral work so hard to grow and when thier is a deficiency of carbonate the problem tends to magnify. Corals are definately able to acclimate to alot of conditions for sure, its just tapping that energy budget tends to keep them riding the line.

I still dont know how to deal with the levated levels of mag and calcium. I can leave the mag to a point but calcium at 500 and a low alk is really unacceptable for a tank full of hard corals. I have been telling folks to just switch salt brands to avoid it, it that your basic answer to???


Mike

Boomer
01-13-2005, 07:29 PM
Collin

The std chemical oceanographic method for measuring salinity is Conductivity. It is based on the std state of equation, found in any seawater manual or chemical oceanography text.


The std equation of state for seawater is

K15 = Conductivity of seawater sample / conductivity of std KCl solution @ 15 C 1 ATM and
the KCl being at 32.4356gkg

S = 0.0080 - .1692 K15 exp 1/2 + 25.3851 K15 + 14.0941 K15 exp 3/2 - 7.0261 K15 ² + 2.7081
K15 exp 5/2

If the conductivity of the sample is 53, 225 uM and it is the same for the KCL, then K15
=1. If you plug that 1 into the equation it = 35 ppt



This is what those 53mS solutions are, std calibrations solutions for salinity via conductivity. You can go to website after website and see oceanic salinity tracks via conductivity. Dr. Frank Millero, an old friend of mine, is a one of the pioneers in this filed. He also is author of;

Chemical Oceanography

Collin's reading assignmet, he is not special :lol::D:lol:

Unesco (1981b) The practical salinity scale 1978 and the international
equation of state of seawater 1980. Technical Papers in Marine
Science 38, Unesco/ICES/SCOR/IAPSO.

http://www.umass.edu/tei/mwwp/acrobat/sm2520salinity.PDF

http://www.es.flinders.edu.au/~mattom/IntroOc/notes/lecture03.html

Calculator;( don't anyone confuse density with SG, not the same)
http://fermi.jhuapl.edu/denscalc.html


Randy also did this long ago and has some of your concerns in it.

http://www.aquariumfish.com/aquariumfish/detail.aspx?aid=1804&cid=124&search=

DisturbedReefer
01-13-2005, 07:55 PM
So if the calibration standard is 53mS and this is what I am calibrating with, do I still need to make a compensation for NSW as you would for the refractor? Here is a shot of the scale that comes with the pinpoint unit. I just want to make sure that I'm getting the salinaty part right since I'm one of the unfortunate ones that is using Oceanic as well...I have a full bucket of IO ready to go for my newest tank project ;)

cwcross
01-14-2005, 11:43 AM
I still dont know how to deal with the levated levels of mag and calcium. I can leave the mag to a point but calcium at 500 and a low alk is really unacceptable for a tank full of hard corals. I have been telling folks to just switch salt brands to avoid it, it that your basic answer to???


Mike

That is the easiest thing in my opinion. The only other option is to buy reagent grade NaCl to supplement salt. The only reason that they don't want to change formulation is a cost and profit issue. Their cost will be higher if they add another 0.8 lbs of NaCl / hundred gallons mixed water. Easy to fix...just costs more. They would rather sell a more profitable salt and let the corals eat the difference. However, the other option is just to run salinity at 1.023 or so. I doubt this really has much impact.

Collin

cwcross
01-14-2005, 12:42 PM
So if the calibration standard is 53mS and this is what I am calibrating with, do I still need to make a compensation for NSW as you would for the refractor? Here is a shot of the scale that comes with the pinpoint unit. I just want to make sure that I'm getting the salinaty part right since I'm one of the unfortunate ones that is using Oceanic as well...I have a full bucket of IO ready to go for my newest tank project ;)

After reading some of boomers homework assignment...I would say no. You are OK with the standard calibrant for all intents and purposes...Collin

DisturbedReefer
01-14-2005, 01:57 PM
Yeah, that's what I was getting out of it as well, just wanted to make sure I wasn't missing something there...Boomer?

Boomer
01-14-2005, 06:11 PM
Just to back up Colin, no corrections are needed, UNLESS your meter does not have temp compensation and I pretty sure it does.

Electrokate
02-11-2005, 03:20 PM
Just to throw a little monkey wrench into our expected outcomes...
I had a problem with a reputable brand of salt which sent my tanks into a tailspin from hell. Tried to correct with water changes, got worse, finally made up new water, circulated and heated for a day and then tested it at 1.025 (per plastic cheapo meter)... Got 620 ppm for the Ca and dKh 6, ph 8. Emailed the company, they said my test kits are bad. Got 3 more brands to test alk and they all said the same low result. For the Ca bought a Hagen kit, got 760 Ca. Found a different batch of Hagen Ca and tried that, got 740 ppm. Gee, should have stuck with the results from TropicMarin's kit! "Only" 620 which the salt manufacturer agreed was way too high! I didn't email the salt manufacturer again as since found others have had the same result from this brand-random bad buckets. When they claimed to have found them on lists such as this everyone poo poohed it, impossible, the manufacturer has a stellar reputation! So am not going to name them here. Besides, that batch is sold and gone, and any manufacturer could be next.
Anyways, my ph crashed but since I am a test nazi I caught it before too much damage was done. A friend using the same batch of salt was not so lucky, he lost every living thing in his tank. All he noticed was low ph as he uses 5 in 1 test strips and nothing else, and doesn't know how to even really read that test.

Previously I had taken a whole bunch of brands of aquarium test kits and run them side by side. Found some were really entirely useless right off the shelf, others fairly consistent but all slightly different. The tests I am now using are by salifert for alk, Aquarium Pharmaceuticals for nitrate and all others by Hagen. Some of the other brands really stunk... amazing. One you couldn't even get any liquid out, the precipitate had solidified completely at the top of the bottle, not sure how that happened... It was brand new off the shelf from a major box store. Have stuck with the brands that are cheap and likely to be used by my friends and customers. Don't think customers are going to be happy if I try and sell them the really expensive kits so want to find the best of the cheapos. As I work in the industry, don't think I should mention names of the real stinkers. We still sell salt by the company that sent the bad batch, gee it was really cheap that time too, think they knew. We don't sell the test kits by the company that failed my kitchen table comparison though, and the salt manufacturer has been good since, not that I will use them again.

Moral of the story, even the best and most reputable manufacturers are putting out unreliable batches now and then, and the test kits are not all that accurate either.
Also was using a reputable brand of 2 part additive and both bottles had significant precipitate in the bottom. I have no idea how much of the chemistry made it out of that bottle and in what proportions, which sucks.
Think I will keep doing my little chemistry experiments...
I have part of an art degree and that is my higher education. Should have stuck with my original interest-non mammal vet med. Art school was pretty light on the whole chemistry aspect of our education. All I know is what you guys teach me so thanks for doing so!
Kate

cwcross
02-11-2005, 08:24 PM
Well Kate,

looks like you have common sense enough to make up for your lack of chemical knowlege. Interesting info and evidently a good catch on your part.

You elaborate on a point I was trying to make a while back. When comparing results of different people using different test kits in different environments...results can differ significantly.

One persons Ca of 380 is anothers persons 450.

Observational skills, being consistent, keeping logs and sticking with what works are very important in this hobby...

regards...Collin