How high is too high?

jgvergo · Jan 4, 2019

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I just recalibrated my Apex PH probe and, to my surprise, the PH of the tank is higher that I thought. My daily PH swings are consistently between 8.2 and 8.5 (I dose alk at night and have my sump light on at night to minimize the swings).

Most articles recommend a PH of between 8.1 and 8.4. Is the fact that I'm seeing 8.5 a problem? What are the ramifications of a high PH? At what level should I be concerned?

saltyfilmfolks · Jan 4, 2019

8.5 is good.

nereefpat · Jan 4, 2019

Ramifications of too high pH would be precipitation of calcium carbonate. If you aren't seeing that, than you most likely are fine.

Randy Holmes-Farley · Jan 4, 2019

IMO, high pH is not a concern until it gets to 8.6 or higher. If it is above pH 8.5, more aeration will lower it unless the alk is above 12 dKH.

jgvergo · Jan 5, 2019

Randy Holmes-Farley said:
IMO, high pH is not a concern until it gets to 8.6 or higher. If it is above pH 8.5, more aeration will lower it unless the alk is above 12 dKH.

Thanks Randy. My Alk is in the 8.5 - 9.0 range, so I think I'll be OK.

As for aeration, I'm confused by what you said. I thought aeration drives CO2 out of the water, which reduces dissolved CO2 and carbonic acid, resulting in a higher PH.

jgvergo · Jan 5, 2019

nereefpat said:
Ramifications of too high pH would be precipitation of calcium carbonate. If you aren't seeing that, than you most likely are fine.

How do I see if I am getting precipitation of calcium carbonate? I do get some clumping of my sand. I periodically break it up by hand. Is there something else I should be looking for?