Ph?

[SpartyOn]

Why does it drop at night? when i look at my apex the Ph consistently drops at night. Why???

[dirtycontour]

During the day, when your lights are on, photosynthesis turns carbon dioxide into oxygen raising your pH. At night, when your lights are off, respiration occurs which is basically the opposite of photosynthesis.

[hollister]

Its normal due to daily tank activity's. But it does tend to level out as tank ages. Always test in the morning for best readings....

[downbeach]

Good article here:

http://reefkeeping.com/issues/2007-05/rhf/index.php#6