How do I keep alkalinity low while dosing kalkwasser for pH?

[20 gallon nano]

What I'm trying to ask was , if I use lime water to keep my ph stable at 8.3 would that also keep my alkalinity stable at around 12 dkh?

 

[KingBlingTX]

I wouldn't worry so much about trying to dose kalk to maintain a certain pH. The goal for dosing kalk would be to maintain your alkalinity. Other factors (such as CO2 levels) affect the pH that can drive it up or down (alk will swing some as well).

 

[20 gallon nano]

I have a keefkeeper with a ph probe and I just thought if that would be true that the pH would stay stable with alkalinity number then I wouldn't have to test for alkalinity since the pH number would show me what it's at.

 

[rock_lobster]

The pH shouldnt be that low with an alkalinity over 13. The tank is not aerated so it is storing CO2 or else the CO2 content in the area is higher than normal. Also it could be that you have an inaccurate measure of either your pH or ALK because those 2 are pretty far out of line.

 

[Randy Holmes-Farley]

So if my ph stays stable at 8.3 does that mean my alkalinity will stay at around 12?

pH is not a good indicator of alkalinity because pH is determined by both the alkalinity and the CO2 level in the water. Carbon dioxide levels vary substantially due to photosynthesis, respiration, and the fact that aeration of reef aquariums is never perfect.

 

[20 gallon nano]

I recently ran a air line from my skimmer intake to outside of my house, this helped dress air go into my tank, this actually increased my ph by about .05 because I'm getting less co2 entering my tank. I also noticed if I don't airate the surface of my tank, that also increased my ph my about .01 since the surface is no longer mixing with my inside house air that's filled with co2.

 

[20 gallon nano]

 

[tapeworm123]

Hi I’ve had the opposite problem not being able to keep up my alk up with kalk. I think it’s due to me running a air line to the outside air and not having enough co2.

 

[Randy Holmes-Farley]

Hi I’ve had the opposite problem not being able to keep up my alk up with kalk. I think it’s due to me running a air line to the outside air and not having enough co2.

I doubt that is the issue.

How high is the pH? If it is too high (pH 8.6 or greater) due to too much limewater and not enough CO2, more aeration will solve the problem. [emoji3]

 

[tapeworm123]

Ph at night is 8.1 an during the day 8.17. My calcium is raising over 500 ppm an my alk is 117 ppm. Meanwhile I dose 400 ml of fully saturated kalk to a 120gallon tank. It is about half stocked with mini colony. I’ve tryed dosing baking soda to raise up the alk to balance the tank but my acros just start to STN

 

[tapeworm123]

I am getting decent growth out of a few acros and Monti an torches but some acros are reseeding

 

[Randy Holmes-Farley]

There is no shortage of CO2 then. Limewater often cannot keep pace with demand due to its limited solubility in fresh water.

 

[tapeworm123]

The alk in kalk comes from co2 correct should I add more co2 or more kalk .

 

[Da8]

If you have very high alk you can try rise CA so it demands more kh decreasing the value in your tank

 

[Randy Holmes-Farley]

The alk in kalk comes from co2 correct should I add more co2 or more kalk .

No, unless your tank pH is very high, you never need to add any CO2. There is plenty in the air and water. If the pH gets above 8.6, you should increase aeration to add more CO2.