Kalkwasser ATO PH

[cperry7467]

I currently use 1 tsp per gallon of kalkwasser in my ATO RODI water. At peak, the PH of my tank is at 8.4. However, my alk and calcium are still dropping more than I would like during the week so I'm considering bumping it up to 1.5-2tsp of kalkwasser per gallon. My question is will that cause the PH of the ATO RODI water to go up even more, thereby causing my tank water to go up even more and above 8.4? I considered using my PH meter on a gallon of RODI with 1 tsp and then increasing it to 2 to check the impact on PH but I figured I would ask first.

 

[Randy Holmes-Farley Verified Community Expert]

It may go up some, yes, and that is fine. I'd start to worry about getting more aeration if it got above pH 8.55 or so. The only apparent issue with pH above 8.55 is that calcium carbonate precipitation on pumps and such increases as the pH rises, but many hard corals may grow faster. My tank using limewater ran for years at pH 8.35 to 8.55, until I got new storm windows and the pH declined a bit.

FWIW, the pH of the limewater itself will go from roughly about 12.2 to 12.5 when you go from 1 tsp to 2 tsp per gallon.

 

[cperry7467]

Great thanks! I'll move it up to 1.5 next week and see how it goes. I appreciate the advice! Although I think you forgot to put in the PH for 2 tsp per gallon. It will go from 12.2 to ?

 

[Randy Holmes-Farley Verified Community Expert]

Sorry, 12.2 to 12.5. That may not seem like a lot, but it has twice the pH rise in the tank (at least until the tank sucks in CO2 from the air).