High pH in SPS Reef?

aaron23

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We talk a lot about the parameters of pH being within 8-8.3.
1. Is it that calficiation occurs best between 8-8.3?
2. But what if the pH is above 8.3 during the day? Is it just that calification decreases? Is there harm done to SPS corals if pH is above a certain threshold?
 
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Randy Holmes-Farley

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I do not think pH 8.3 to 8.6 is bad for SPS. At least I have no data to suggest so.

I usually recommend pH 7.8 to 8.5, but the high end is more limited by concern over abiotic precipitation of calcium carbonate on pumps and heaters than any knowledge of problems with organisms.

FWIW, my tank ran pH 8.35 to 8.55 for years, before I got new storm windows and it dropped. :)
 
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Randy Holmes-Farley

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My PH is 9.0 is that bad ??

It would be bad, but I doubt it is real.

The tank would likely be milky white with precipitated calcium carbonate. It also doesn't happen without massive overdoses of the highest pH additives.

How did you measure it?
 
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Kungpaoshizi

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I hit 8.7 in the evening when my skimmer turns on. Made me concerned for awhile but nothing seems to be bothered by it.
I've often speculated that though we aim for around 8.3 right now because that's what a lot of reefs are around, who's to say pre-industrial age the oceans were not 8.5 to 9 ph. (the math would suggest this since the ocean ticks down x amount of ph every year because of the co2 increases)
 
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Randy Holmes-Farley

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I turned my skimmer and return pump off last night for cleaning and my ph jumped UP to 8.55. Normally I peak out at 8.35. What caused this?

Less CO2 being driven in from your home air. I experienced that too when I shut off my skimmer as an experiment.

IMO, aeration is one of the clearest benefits of a skimmer.
 

Heabel7

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Less CO2 being driven in from your home air. I experienced that too when I shut off my skimmer as an experiment.

IMO, aeration is one of the clearest benefits of a skimmer.
Old thread, you say aeration is a clear benifit and have heard that countless times. For that reason i have never shut my skimmer off thinking i could only be helping by adding oxygen to the tank. But, as i read more it is clear that it may actually be driving my PH down with 5 people and a dog in my smallish home. Given its pumping CO2 in all day (PH 8.1 day) would you suggest turning it off at night just to keep the PH up? I seen for the first time last night (apex day 1) that my pH got down to 7.8 and would have dipped further if i did not dose my soda ash at night. I have had 2 mass die offs in the winter time and now think it may be PH related with the house closed up and so many people putting out CO2. I would bet i was dipping into the 7.4-7.5 area..... may be of note i keep my Alk at 7.5-8.

thanks for you help Randy.

Could low PH at night also contribute to very slow coraline growth. Really very little coraline in tank overall
 

Randy Holmes-Farley

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Low pH might deter coralline, yes.

Only way to know on the skimmer off is to try it, but another option is fresh air or scrubbed air to the skimmer, maintaining oxygenation when you most need it: at night.
 
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ZombieEngineer

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Old thread, you say aeration is a clear benifit and have heard that countless times. For that reason i have never shut my skimmer off thinking i could only be helping by adding oxygen to the tank. But, as i read more it is clear that it may actually be driving my PH down with 5 people and a dog in my smallish home. Given its pumping CO2 in all day (PH 8.1 day) would you suggest turning it off at night just to keep the PH up? I seen for the first time last night (apex day 1) that my pH got down to 7.8 and would have dipped further if i did not dose my soda ash at night. I have had 2 mass die offs in the winter time and now think it may be PH related with the house closed up and so many people putting out CO2. I would bet i was dipping into the 7.4-7.5 area..... may be of note i keep my Alk at 7.5-8.

thanks for you help Randy.

Could low PH at night also contribute to very slow coraline growth. Really very little coraline in tank overall
The other benefits of a skimmer far outweigh the benefits of a slightly higher pH. I would try removing it as an experiment to see what effect it will make, but you would be much better off keeping it online and adding a CO2 scrubber to the intake IMO if taking it offline made a significant impact. That way you still get the organic reduction from the skimmer without the pH reduction effect.
 

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