Best way to raise ph? Kalk?

[fixerupper]

Originally Posted by LeanneP

I have a 4 years old mixed reef 90 gallon with 10 gallon sump. My tank is pretty full and I have started to have ph swings now. I am in the process of setting up a calcium reactor but have been dosing for a couple of years now. My ph is going down to 7.7 at night now so I know I need to do something about it. Is kalk the best way for the ph swings? Would using a doser at night and dosing once an hour be enough to stop the swings? Or would it need to be dripping constantly to keep it stable? I do have an extra aqua lifter so wondering if that would work.

Are you using a controller with a pH probe? If so, has it been calibrated recently?
A few months ago I was having weird results testing for parameters. I updated my test kits but my results were duplicated so I was fairly confident they were accurate. As it turns out my refractometer reading had drifted. The 1.026 SG reading was actually 1.030. Naturally this threw off my other readings too.

When I set up my Apex the pH probe was also out of calibration by fair bit. It was in a box for several years before I installed it so I still don't quite trust it. If your test kits are old and/or your probe hasn't been calibrated in a while, it might be a good idea to make sure they are reading accurately before making any adjustments.

[LeanneP]

I do have a ph probe and refractor. Everything has been calibrated recently and all my test kits are new. I had to use chemi clean a few weeks ago and had my tank with air stones for a few days and I didn't notice any increase in the ph so I am convinced it is high C02 in house. I have left the window open over night to see if it would increase the ph but it also didn't help. I have now added kalk to my ato water which seems to be working. When it dumps in it does raise the ph by 0.2 but in Randy's article it says that is acceptable. My ph now doesn't go below 7.8 and the highest it goes is about 8.2. I am guessing if I have more evaporation in warmer months though it may go up.
I am still not sure the kalk will keep it high enough as Mindy said if I get the calcium reactor working though. I have a ph controller but I wondering if it will shut off the C0s too much at night too keep my levels stable.