pH rising at night?

AdamNC · May 3, 2017

Curious as to what would make my pH start to rise at 3:00am as my lights don't turn on until 8:00am. As you can see the normal pattern for the last week.

Best Fish-Jake · May 3, 2017

Do you have a refugium with a light that comes on at night?

BigJim · May 3, 2017

Or did you get up and open a window at 3 AM?

Randy Holmes-Farley · May 3, 2017

I agree that barring lighting, it is either an indoor CO2 in the air issue, dosing of something that has a high pH, or error.

AdamNC · May 3, 2017

No sump, it's an AGA tank with all HOB equipment. No windows were opened last night as it dropped down to 50 last night. And I haven't changed any dosing except instead of NoPoX dosing of 1.5ml I'm down to 1ml a day, but that's done at about 6:00 pm.

And here's my parameters as of yesterday.

Randy Holmes-Farley · May 3, 2017

The NOPOX produces CO2 when it is metabolized. That may happen over several hours, artificially depressing the pH, then it rises when that is done.

AdamNC · May 3, 2017

It's never happened before and I've been using NoPoX since I think last summer. It may be a fluke but I'm just more curious as to why it happened.

Randy Holmes-Farley · May 3, 2017

AdamNC said:
It's never happened before and I've been using NoPoX since I think last summer. It may be a fluke but I'm just more curious as to why it happened.

Well, pH is determined mathematically by the alkalinity and the CO2 level. So somehow the CO2 level in the water is dropping.