[weez1959]

In regards to pH, how high is too high? What are the effects on fish?
How low is too low and again the same question?

The reason for asking is this morning I got up to a pH of 8.3 and now it's a 8.55.

I haven't done the rest of the tests but I will post them later....

Should I be worrying?

[Poseidon]

Nope, don't worry.

Are you using a pH probe, and when was it last calibrated?

[weez1959]

Jeez I feel so stupid, good thing I didn't ry to bring it down!
It was the battery, giving false readings. I recalibrated and now I'm back to low pH! :P

[Ninong]

Originally Posted by weez1959

In regards to pH, how high is too high? What are the effects on fish?
How low is too low and again the same question?

The reason for asking is this morning I got up to a pH of 8.3 and now it's a 8.55.

The goal is stability but it's an elusive goal. We would all like to be able to maintain a constant 8.2 pH to match natural seawater (which used to be 8.3 before the industrial revolution and will be 7.9 by the end of this century the way things are going now).

You will notice that your pH readings are lowest in the early morning and highest in the late afternoon. Or, to be more precise, they will be lowest before your lights come on and highest after the lights have been on all day. This variation is caused by photosynthesis and respiration. An ideal range would be 8.2-8.3 but 8.1-8.4 is still great. You won't really run too much risk as long as your pH stays above 7.8 and below 8.6. Below 7.8 and above 8.6 should be avoided. Another thing to strive for is to have the diurnal swing as tight as possible. For example, 7.9 to 8.4 in a single 24-hr period is not as good as 8.1 to 8.3.

People who use Kalkwasser will drip it at night when the lights are off to mitigate the pH swing. People who have a refugium with macroalgae will light it at night when the lights in the main tank are off for the same reason.

[weez1959]

Thanks! good info...