?Kalkwasser dosing recommendations?

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The R/C Man

Well-known member
Feb 20, 2004
Spokane WA
Hey everyone!

Well I bought some kalkwasser (pickling lime) and was wondering how often to dose, how much and what effects it will have on calcium and alkalinity levels..... As of right now my tank seems to be having a hard time maintaining its alkalinity. Thanks!

25gal Tank
10 gal sump/fuge
Magnesium 1400ppm
Calcium 325ppm
Alkalinity 7DKH
Salinity 1.025


Well-known member
Jun 30, 2003
Mukilteo, WA
Most people who dose, dose on a nightly basis. This is when the PH in the tank is depressed, so a slight increase in PH is good.

The biggest thing with Kalk is the impact on PH. It will boost the PH unless added very slowly (dripped or slow dosed). Kalk's effectiveness is very dependent on your evaporation rate. You can only add as fast as you have room for. Furthermore, even with a high evaporation rate you are limited to how much you can maintain based on your calcium and alkalinity load in your tank. If you only have a few SPS then and your evaporation rate is good (fans on the sump or main tank surface) then Kalk works pretty well.

Good luck and be carefull.



Dec 15, 2003
Tacoma, WA
I'm not sure what if any effect kalk has on alk. I have never been abel to maintain alk levels until I added the calcium reactor, but that may have something to do with my tank size. I top off with all kalk water at 1/2 gallon per day and my ph stays at 8.2 to 8.4.



Oct 14, 2003
DonW, the demand of your tank was probably too much for the Kalk to keep up with, that's why you couldn't keep Alk. stable.

We have about 250gal. with many clams and SPS and it keeps levels pretty stable. Although, I think if I add one for Calcium demanding piece, it may put it over the edge.

Go with pickling lime and save yourself a bundle of money. Although not as pure as aquarium grade, the bad stuff will settle anyways. Shouldn't cause a problem unless your dosing anything but clear liquid.


Mar 15, 2004
The R/C Man said:
was wondering how often to dose, how much and what effects it will have on calcium and alkalinity levels
Limewater (kalk) is a balanced additive, meaning that adds ca and alk to your water in roughly the same proportions that they get used up. Depending on the concentration of limewater you are adding and the amount of evaporation that you have in your system, it will slowly raise your ca and alk levels to the saturation point of your water, as long as you are adding more than is being consumed.

The level changes are generally so slow, however, that most people prefer to use a two part additive to get their levels up to where they want, and then maintain the levels by using limewater for their topoff.

Limewater must be added slowly to your system, or it will not be effective. If you add it too quickly, it will not be able to go through the chemical reactions that produce the end products that your corals need. Also, if added too quickly, it will spike your PH.

I use limewater to replace 100% of my evaporation.
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