Normal for PH to dip a little at night?

[Michael43]

Seems like my ph is pretty much ranging from 8-8.2 It tends to slowly drop at night to like 8-8.05 and seems like in the peek hours of the day its around 8.12-8.2 it does get to these numbers gradually and not all at once. I think its normal due to some photosynthesis but I'd just like to hear it from the experts. Thank you

 

[Cory]

Yes its normal. photosynthesis stopping at night is a major player in ph decrease. Its because plants stop using co2 to prodice sugars. Iirc.

 

[Salty1962]

It is normal as mentioned. If you have a sump with macro algae, run the lighting at opposite times. Helps keep PH at a better level. Mine still runs .08 difference.

 

[Randy Holmes-Farley]

With perfect aeration, there would not be any swing, but there almost always is, so this is evidence that aeration is usually not complete. :)

I discuss pH in detail here:

pH and the reef Aquarium
http://www.reefedition.com/ph-and-the-reef-aquarium/