Ph shift!?

[Fishfinder]

anyone have a possible cause or solution for this ph shift. It's not looking good over the last day. The only thing I did was run some activated carbon 2 days ago. It ran for 24hrs, then took it back off. No changes in dosing or dkh. But a definite downward shift in ph.

 

[Randy Holmes-Farley Verified Community Expert]

Did you close house windows?

 

[Fishfinder]

No change in windows or AC setting. Windows have been closed since feb.

 

[Reeferdood]

Howdy neighbor!
The pH looks to be on the low side to begin with, are you sure the probe is calibrated properly? The trends don't really look all that bad but even on the high point it is on the low end. Tell about your setup and other parameters, and equipment that you use.

 

[Randy Holmes-Farley Verified Community Expert]

No change in windows or AC setting. Windows have been closed since feb.

If nothing changed (no change in additives, alkalinity, aeration, or number of people around the tank), then it might just be a sign the probe needs to be recalibrated.

 

[Reeferdood]

I know how a house with closed windows can suppress the pH, I actually run an airline outside to get fresh air to the skimmer.

 

[Fishfinder]

@Randy Holmes-Farley you commented on my ORP thread. Would running carbon and the elevated ORP cause a down shift in my ph?

 

[Randy Holmes-Farley Verified Community Expert]

@Randy Holmes-Farley you commented on my ORP thread. Would running carbon and the elevated ORP cause a down shift in my ph?

Running carbon does not usually cause much pH change (certainly not after it has been in a bit), but any pH change impacts ORP.

 

[Fishfinder]

What do you think would cause the lower ph? Possibly a sign of less coral uptake? Or can ORP effect ph? Or does it only work the other way around?

I don't really know how to correct it until I know what caused it

 

[Randy Holmes-Farley Verified Community Expert]

What do you think would cause the lower ph? Possibly a sign of less coral uptake? Or can ORP effect ph? Or does it only work the other way around?

I don't really know how to correct it until I know what caused it

ORP has no effect on pH. pH effects ORP.

I don't think there is anything to correct, if alkalinity is normal, except aeration. More fresh air around the tank and to the skimmer will raise the pH.

 

[Fishfinder]

Ok thanks for the help, I'll try recalibrating and see if it shifts.

 

[kevin_e]

I run my skimmer outside and have it plumbed to CO2 scrubbing material. My pH went from 7.5-7.7 to 7.85-8.2. big difference. When people aren't home, pH has gone up even higher. Weekends it tends to be lower.

I'm in a 1200 sq ft place in Florida with 2 adults and 3 dogs. CO2 gets high with our closed off place.