Does high ph affect fish and coral?

[Aquavaj]

My tank is swinging from 8.3 to 8.8 during the day. Thought it was a bad apex ph probe but a new calibrated probe is giving similar readings. I dont know what's causing it to be so high. It's a standard 120g with a gyre on one side, a wavemaker on the center overflow and 2 power heads on the other end. Returns also pointed towards the surface so there is plenty of surface agitation. It's been pretty warm so plenty of windows opened.

I tried dosing 100ml of vinegar last night and it dropped down to 8.4. Am I gonna have to continue dosing? I do dose all from 2 part but only 6ml a day to maintain.

1.026 sg
8.5 dkh
450 ca
1440 mg

 

[ihavecrabs]

I know people that would kill for a ph in that range.

Definitely do not dose anything to change pH as it is not significant while in an appropriate range. More important is keeping your alkalinity stable and typically dosing products that adjust your pH significantly impact alkalinity.

Also to note, vinegar dosing is typically used as a carbon dosing method (feeds bacteria and gets skimmed out); however, at much lower doses. That much vinegar is likely to cause a significant bacteria bloom and suffocate your livestock so definitely be careful with that!

IMO, your pH is fine and I wouldn't stress it at all..

 

[ihavecrabs]

You could also try dosing at night only. That will keep the diurnal swing a little less since bicarbonate (Alk portion of 2-part) raises pH.

 

[Randy Holmes-Farley Verified Community Expert]

pH 8.8 at that alkalinity is, IMO, most likely test error (despite the remeasurement). I’m not a fan of controllers for pH measurement. If it is real, the tank is seriously lacking in aeration.

 

[Aquavaj]

pH 8.8 at that alkalinity is, IMO, most likely test error (despite the remeasurement). I’m not a fan of controllers for pH measurement. If it is real, the tank is seriously lacking in aeration.

It is spot on when I retest the new probe with the calibration fluid - 6.99 and 10.0. Also retested alk yesterday (same exact way I've always tested) and it's at 8.3dkh. I have 2 wavemakers and 2 power heads going too so I'm confident there's plenty of aeration. Really stumped on what's going on.

 

[smartwater101]

pH 8.8 at that alkalinity is, IMO, most likely test error (despite the remeasurement). I’m not a fan of controllers for pH measurement. If it is real, the tank is seriously lacking in aeration.

But isn't lack of aeration the cause of low pH? I thought things like skimmers and scubbers and opening windows was for higher pH/aeration...

 

[BeejReef]

I'm a windows open person too and occasionally run as high as 8.5 or 8.6. My test kit doesn't even go up to 8.8.
Yeah, a lot of people would like consistently elevated PH, but I've found very little literature on how high is too high for fish and corals. Usually, it's in relation to a ph spike one might expect with a limewater OD. Nothing on how high it can stay if it's relatively consistent and stable though.