kalk and pH

[jadeguppy]

I am trying to read through articles, but still have a question.

Is dosing kalk (pickling lime) a good way to keep pH up? Mine appears to be dropping .3 to .4 per day. If so, is adding 1/2 tsp to 1 tsp to my gallon top off water a good way to do it? I don't have an ato at the moment. The tank is 40g and evporates about 1g/ day.
Thanks!

[bertoni]

What is the alkalinity level of the tank? What's being supplemented currently?

Dripping lime can help with pH, but it does add calcium and alkalinity as well.

[jadeguppy]

I don't have a test for alk. It is on its way. When I tested the cal it was low. So I added kalk based on the pH.

[Randy Holmes-Farley]

Limewater (kalkwasser) is not a suitable way to raise low calcium levels. It boosts alkalinity too much.

This article has more:

Solving Calcium and Alkalinity Problems
http://www.advancedaquarist.com/issues/nov2002/chem.htm

[jadeguppy]

Randy, I'm confused. What is kalk for?

[Randy Holmes-Farley]

It is for routine supplementation of both calcium and alkalinity in the right ratio that corals use it. But you cannot boost one without boosting the other, and a 100 ppm boost in calcium will boost alkalinity by 5 meq/L (14 dKH).

[bdare]

Originally posted by Randy Holmes-Farley
Limewater (kalkwasser) is not a suitable way to raise low calcium levels. It boosts alkalinity too much.

This article has more:

Solving Calcium and Alkalinity Problems
http://www.advancedaquarist.com/issues/nov2002/chem.htm

Hey Randy,

Can you help me understand this? I've always thought that Kalk was a "balanced" additive. How is it then that it will boost Alk?

For example, what would the consequences be of using diluted (not saturated) limewater in an ATO in a FOWLR system?

Thanks,
Ben

[Randy Holmes-Farley]

It is a near perfect balanced additive, assuming that you are using it to balance consumption by corals and such, which use a particular fixed ratio of calcium to alkalinity (20 ppm calcium to each 1 meq/L (1.4 dKH) of alkalinity. I use a less than saturated solution to maintain my tank.

If you try to use it for any other adjustments, like boosting calcium a lot, it will fail, because it will try to boost alkalinity by a huge and inappropriate amount.

[jadeguppy]

So using kalk to keep my cal level up (drops due to coral use) is fine or adds too much alk? I will have the alk test kit in this week, but for now I don't know the exact level. However, the drop in cal and especially pH appear to steadily drop at a predictable rate over time. This is why I assumed (I know, bad thing to do) that the low cal reading is due to coral consumption and is also showing in low pH readings. Is it possible to add too much kalk and still have a low pH reading without a CO2 injector? I've been dosing kalk based on the pH reading after I noticed it and my cal level were down. Honestly, the Pinpoint pH monitor is easier to keep tract of than doing liquid cal tests.

[Randy Holmes-Farley]

So using kalk to keep my cal level up (drops due to coral use) is fine or adds too much alk?

If it is being depleted by deposition of calcium carbonate, it is fine. if it is being depleted by water changes with a low calcium mix, it is not.

I'd check the alkalinity before worrying about whether you are dosing the right amount. Use alkalinity as the gauge as it is much more sensitive to over or under dosing than is calcium.

[jadeguppy]

Okay, I think I understand a little better now. This is between water changes so it is coral use. I'll be sure to check both when I make up my next batch of salt. I use reef crystals and there seems to be a debate about them on the other thread. Thanks for the help. I'll kep reading the articles until I fully "get it", but for now I think my tank is okay even if I don't fully understand. I guess I should have studied more in chem class.

[Randy Holmes-Farley]

You're welcome.

Good luck.