Why is my PH rising?
 

PH has gone from 8.08 to 8.37 in 4 days. Using a PH probe.

Don't use CO2 or any reactor. Just refugium and 2 skimmers.

What causes PH in a reef tank to rise?

Corals and fish seem happy but I'm concerned over the rise.

Fresh air causes it to rise

you don't dose anything I assume, so first I would recalibrate your ph probe to make sure its still within proper working range. It would be beneficial if you can get another tester to confirm your findings. reason I said this is ph usually drops by itself not rise.

Thanks I'll do that tonight.

Gripen I think that you should stop peeing in your tank too its not going to help it any.:mrgreen:

honestly. last week i opened my windows for a few hours and my PH rose from 8.05 to 8.3 in a matter of few hours

Yes I have always ran fresh air line in the winter to my intake line for air for the skimmer... helps alot.

my pH has been up a bit too. I installed an HRV this winter got me thing here the fresh air in the room now could be doing it too.

pH
 

The pH of most oceans is 8.3 I worry when my pH is less than that. pH decreases in the night due to CO2 build up, then rises when the lights come on and photo synthesis begins to use the CO2. I think the Ideal pH is around 8.3

"The pH of marine aquarium water is intimately tied to the amount of carbon dioxide dissolved in the water. It is also tied to the alkalinity. In fact, if water is fully aerated (that is, it is in full equilibrium with normal air) then the pH is exactly determined by the carbonate alkalinity The higher the alkalinity, the higher the pH, and equilibrated with air having extra carbon dioxide as might be present in a home (1000 ppm). Clearly, the pH is lower at any given alkalinity when the carbon dioxide is raised. It is this excess carbon dioxide that leads to most low pH problems for reef aquarists"
That was a quote from one of Randy Holmes articles. With fresh o2 in the house it could affect the ph in our aquarium , also if your refugium has seen good growth over the last bit, it could also take up amount of co2 in the tank and by reducing co2 level we know it will also raise ph. Just food for thought.