View Full Version : Low Alkalinity

03-30-2006, 10:52 AM
I have been keeping a 180gal Reef tank for 1 year and 6 months. I have always had problems keeping the alkalinity around 3.00. For more than a day or two with out adding baking soda and washing soda at a 6 to 1 ratio. Normal maintenance on the tank is as follows 20% water changed every two weeks. Dose tank with CalxMax Part A & B at 50ml every other day. I also dose the tank with baking soda & washing soda at least once a week depending on alkalinity test results. With doing this I am able to keep the alkalinity at around 2.70 or so. But it is a real battle to keep it stable.

I tested my water last night and my alkalinity was again down to 2.29. My calcium stays stable at 490 and my PH was 8.0.

Above was just a bit of background on my current setup. Now to the reason I am writing this. This weekend I am upgrading my current tank to a 450gal tank. On the new system I do not want to have this battle with my alkalinity. Any suggestions on how to resolve this issue.

03-30-2006, 11:04 AM
Drop your calcium level and you will be able to keep your Alk up.
The corals actually do better with Ca 350-420. Alk is the main thing use anyway.
Basicly you are unbalanced skewed to CA instead of having a ballaced system.
Go to Great Threads on this board. Then go to Calculators, then go CA/Alk calculator. It will tell you what ballanced is. Basicly the best way, and cheapest would be a large water change, with no CA added to the salt, then let Ca fall while keeping Alk at the point you want it.
Are you using Oceanic salt?

03-30-2006, 08:35 PM
I have tried lowering my calcium before but my coral did not like that. With my calcium at 490 my corals have doubled in size and are very healthy. I have never added any CA to my salt or my water change water. No I am not using Oceanic salt I am using Tropic Marin salt mix.

03-30-2006, 10:17 PM
I dont understand. Not arguing, just trying to help. What do you mean your corals didnt like lowering the CA? What did you lower it to?
To increase alk, its my understanding, that CA will have to be lowered. I may be wrong. I have been before.
What is your Mg level?
I do know that it easier for corals to build thier skeleton, if the ca level is lower, and they dont have to pump as much ca out of the cell and since the level is lower in the water, its less work.

03-30-2006, 11:35 PM
Steve is exactly on the money. Your calc. is way to high and is keeping your alk down, samething well happen in reverse is you get your alk to high. The bucket well only hold so many marbles and if you fill it mostly with calc ones you well have no room for alk ones. The idea is not to see how fast you can get your corals to grow but to keep things in balance. 7.7 dkh and 400 calc is natural levels. You need to quit adding the A of the calmax and just add the B part. until you get things balanced.

03-31-2006, 02:09 AM
Calcium levels above 420+/- ppm are really not that good for your corals. You'll see good skeletal growth, but at the expense of tissue growth. It's an energy budget thing, the coral is burning too much energy trying to rid the tissue of Ca, so you get good skeleton growth, but the tissue suffers.


03-31-2006, 07:51 AM

I have had my calcium down to about 400 before but at that level I would not see the polyp extentions from my coral that I see now. Plus my leathers would not open as big as they do with my calcuim at 490. I don't known what my mg level is because I have not tested for that.

I have always been told that calcium should be between 380 - 480 mg/L and alkalinity should be 2.3 - 4.0 meq/L. This is also the levels that are recommended in The Reef Aquarium Science, Art, and Technology Volume Three by J. Charles Delbeek and Julian Sprung.


Several months ago I did stop adding part A of the Calxmax and just dosed the part B. My calcium did drop a little but my corals did not like it at all. Everything looked very sick and was not opening fully. So I went back dosing both A & B and the tank looked 100% better then when I was not dosing part A.


I have not seen any loss in tissue. I have been able to save several corals that where dying in other peoples tanks. I have attached two pictures of my current tank.

03-31-2006, 08:35 AM
Ok I hear you. Your alk can not come up while the Ca is that high. Any alk, added to bring it over that level will only pecipitate out of solution on the rock and sand.
If you tank needs to have CA that high to operate, then your alk will have to be that low.
What is the alk and Ca of freshly mixed Tropic Marin saltwater at 35ppt?
Please understand this is in no way a attack on you, or anything. I really just want to help.
Polyop extension has very little, to nothing to do with the a CA level difference of 405-490, except that the coral is haveing to aquire more energy just to lay down a skeleton. You wont see loss of tissue, you will se much slower tissue growth.
I cant tell you what to do, I can share what I have learned. I am not trying to sell you anything. I dont make supplements nor own stock in the companies that do.
I can say you would save money, and your corals would work less, to make more. If the ca level was lower. Thats the only true answer I can give you.