high pH

Question
Help! I have had my 45 gallon tank for over 6 years. It had 5 fish, mushrooms, feather dusters, snails, crabs etc. I have crushed coral, lots of live rock and a penguin biowheel filter. The other day my hippo tang and fox face died overnight.  I have had these fish for 4 plus years and they were very healthy. I was worried and tested the water, and the pH was 8.8! I re-tested with same results. I bought a new kit in case the chemicals were old. Still 8.8. I tested tap water as a control and it was 7.4 (normal). I buffered the tank with Proper pH 8.2 and the next day tested again. Still 8.8. So, in an act of desperation,  I changed 75% of the water (I know, a lot) and buffered the new water, added Aquasafe. I re-tested the tank. Still 8.8!!!! I'm stumped. The only change to the tank recently was I switched the one-wheel Pengium Biowheel Filter over for the two-wheel Pengium BioWheel Filter and added two new carbon filters. I did not rinse the filters as well as I usually do. I have tested the amonia, Phosphate, Nitrate and Nitrite and all are basically zero. The salinity is 1.023 (specific gravity). What is driving my pH up so high? How can I lower it. And i I lower it, Im afraid to lower it too fast incase it stresses the fish. Any ideas?

Answer


michelle,

I have never come across a situation like this one.  In most cases at time goes on ph drops and needs to be brought up to 8.1-8.4.  All of my texts suggest that ph will drop on it's own but for you it has not.  Try to buffer it down slowly.  Also most liquid ph reducers are too weak for use in saltwater you will need a powdered buffer.

I have read that ph will raise at night due to to high amount of carbon dioxide.  Let me do some more reading for you and try to find a solution.  Also try 25% water changes every other day.

I am sorry that I could not be of more help to you.
Todd