Should my tank's pH rise in the evening?

[FishPharm]

I have a question with regards to fluctuations in pH over a 24 hour period. I thought I read here in the RC forums that most peopleââ"šÂ¬Ã¢"žÂ¢s pH drop in the evening after the lights turn off. My pH rises from 8.0 to 8.3 in the evening. I have a fuge on a reverse lighting schedule. Calcium reactor and kalkwater drip, with cheato in the fuge. Isnââ"šÂ¬Ã¢"žÂ¢t the pH suppose to drop off in the evening? Or do I have this backwards? Thanx.

 

[Billybeau1]

Mine rises throughout the day and peaks at night. Randy told me this was due to photosynthisis. Mine starts out at 8.08 in the morning and rises to about 8.25 at lights out.

 

[FishPharm]

I don't have alot of corals, though I do have a heavy bioload as far as fish are concerned. My pH stays around 8.05-8.15 during the day. After the lights go out and throughout the evening prior to the lights coming back on my pH is up around 8.3. Isn't this unusual?

 

[Billybeau1]

How close is your probe to your lighting ? Electrical interference will cause a probe to read wrong. Just a thought.

 

[Randy Holmes-Farley]

When do you add the limewater?

When do the refugium lights come on?

The refugium may be driving the pH in a reverse fashion if it has more photosynthesis going on than the main tank.

 

[FishPharm]

Billybeau1: The probe is located in the return chamber of my sump and situated very low in the water. It is also away from electrical sources.

Randy: I have a 55 gallon drum dripping kalkwater at a constant drip 24/7. My fuge light which is located in the center compartment of the sump comes on right after the halides above my display turn off for the day.

 

[Randy Holmes-Farley]

My fuge light which is located in the center compartment of the sump comes on right after the halides above my display turn off for the day.

I expect that is why the pH rises into the evening then. There is nothing wrong with that.

 

[FishPharm]

OK. Thanx Randy.

 

[Randy Holmes-Farley]

You're welcome.

Happy Reefing.