bjhubb

My pH has been a little low every now and then, around 7.8-8.0. I was wondering if it probably had to do with my high calcium, which is around 600. Nitrites are 0, ammonia 0, nitrates 15-20, DKH 12. I used dkh buffer a couple of times last week til I got the ph up to 8.2 but now it is back to about 7.9-8.0. Any ideas?

cerianthus

It is possible when buffer is added (carbonate anion), it can bond with Calcium cation thus precipitate as Calcium Carbonate. Water chemistry is very complex since lots of factors are involved especially in S/w which consist of more dissoved solids.

Does your tank have any LR or Coral Rock? These rock can help you stablize pH along with small water changes (removes acidic substances, for example some nitrate in water can be found in form of Nitric Acid, HNO3, CO2 in water as Carbonic Acid, H2CO3, etc).
Dont get nervous, nothing will blow up, just an example.

Dont know much about your tank and how many, kind of fish, amt of food, etc.

bjhubb

I have a 75g reef tank. About 75lbs. of live rock and 25lbs. base. I mainly have LPS and soft corals.