Daily pH Swing

[cypho]

I'm having recurring RTN issues that can't seem to pin down. Salinity, Calcium, Alkalinity all seem fine. I recently added a pH probe hoping it would tell me something new.

Does this look acceptable for a daily pH swing?

 

[jetmaker]

That's fairly normal.

 

[Randy Holmes-Farley Verified Community Expert]

I agree that is normal and unlikely to be a cause of RTN.

If you want to reduce it, more aeration will reduce the swing, but it's not important, IMO.

 

[AcroNem]

8 in the morning and 8.3 at night for me. I wouldn't say that's the issue.

 

[Randy Holmes-Farley Verified Community Expert]

FWIW, I,discuss pH issues, including the pH swing, here:

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

 

[vic5hands]

You could add a light on your sump to reduce the PH swing. Program the light for night time. This helps

 

[cypho]

Thanks for the advise.

Without any other theories to explain the random coral death (this week the tissue on two acros literally turned into dust/smoke over the course of a few hours) I decided to try controlling the pH with kalkwasser. I told my controller to dose kalk when the pH is below 8.18. It worked surprisingly well at preventing the night time pH drop. I was not using Kalkwasser at all before, just 2-part for Ca and Alk.

Too soon to say if this will end the RTN. Sounds like the consensus is that it won't. But as long as it doesn't make things worse there is no harm in trying.

( the line is smoother because I added some noise filtering to the sensor reading routine, it has nothing to do with the kalkwasser)

 

[Randy Holmes-Farley Verified Community Expert]

FWIW, many people dose their limewater at night to raise the minimum pH that is attained.

Just be sure the alkalinity does not rise too much.