Deciding to dose kalk in my 20g?


Active Member
So I'm wanting to get my PH up a little higher, it gets as low as 7.8 and I'm wanting it to stay at a stable 8.0 or 8.2 and have been reading up on this. I was looking at getting to kent marine 1400ML dosing container and was wondering if this is enough of a container for my 20g with a 10g sump? I have a mix of coral in my tank right now but once I get my PH higher I want to get some more LPS & SPS. Thanks for you time.


I just recently started to use Kalkwasser in my 55 gallon and what I do is to mix up a 5 gallon batch and then put it in my top off bucket. I was dosing it separate but all that was happening is my top off wasn't being used. I'm not sure if that will be enough or not. I think it will depend on the demand of your coral and how much you need to add each day.

bang guy

While dosing limewater will tend to maintain a slightly higher PH, it should not be used for that purpose.

If you have coral demand for Carbonates then sure, good idea. But if your Carbonate demand is low then limewater will eventually start to cause problems.

Have you attempted to discover why your PH is lower? Using limewater to raise the PH will work but it will just mask the problem(s). I'd suggest finding the problem, fixing that, and then think about dosing limewater.



If your PH dips to 7.8 at night and rises during the day then you should be ok since a good PH range is 7.8 - 8.3. The reason the PH will drip at night is because of the increase in CO2 throughout the over night hours. I agree with Bang that you should be careful getting your calcium too high so you might want to test for it before dosing it.

Here are a few things that could be casing you problems with your PH.
1. Due to CaCO3/CO2 Reactors
2. Due to High Indoor Carbon Dioxide Levels
3. Due to Low Alkalinity

For item number 3 try this test (I got this online):

Remove a cup of tank water and measure the PH. Then aerate it for an hour with an air stone using outside air. The pH should rise if the pH is unusually low for the measured alkalinity (if it does not rise, most likely one of the measurements (pH or alkalinity) is in error). Then repeat the same experiment on a new cup of water using inside air. If the pH rises there too, then the aquarium pH will rise with more aeration because it is only the aquarium that contains excess carbon dioxide. If the pH does not rise inside (or rises very little), then the inside air contains excess CO2, and more aeration with that same air will not solve the low pH problem (although aeration with fresher air should).

I personally can not keep my Calcium over 350 so which is the reason I dose using my auto top off and my PH still drops to 7.9 - 8.0 at night.