Ph is now reaching 8.7 at peak

lubeck

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I dose kalk and 2 part and now see my ph hit 8.7 at the end of the photoperiod. I feel like this could be an issue for the sps. Thoughts on how/if I should lower?


I confirmed the ph probe is calibrated.

4DF4DD8F-4BC2-4844-AF4E-7B32028D6412.png
 

gbroadbridge

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I dose kalk and 2 part and now see my ph hit 8.7 at the end of the photoperiod. I feel like this could be an issue for the sps. Thoughts on how/if I should lower?


I confirmed the ph probe is calibrated.

4DF4DD8F-4BC2-4844-AF4E-7B32028D6412.png

You may think you have calibrated the probe, but did you use fresh calibration buffers after cleaning and rehydrating the probe?.
 

Randy Holmes-Farley

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If, in fact, the pH is accurate at pH 8.5+, then the tank needs more aeration and simple aeration will reduce the pH a lot.

Try this test using inside air:


The Aeration Test

Some of the possible causes of low pH listed above require an effort to diagnose. Problems 3 and 4 are quite common, and here is a way to distinguish them. Remove a cup of tank water and measure its pH. Then aerate it for an hour with an airstone using outside air. Its pH should rise if it is unusually low for the measured alkalinity (Figure 2). Then repeat the same experiment on a new cup of water using inside air. If its pH also rises, then the aquarium’s pH will rise simply with more aeration because it is only the aquarium that contains excess carbon dioxide. If the pH does not rise in the cup (or rises very little) when aerating with indoor air, then that air likely contains excess CO2, and more aeration with that same air will not solve the low pH problem (although aeration with fresher air should). Be careful implementing this test if the outside aeration test results in a large temperature change (more than 5°C or 10°F), because such changes alone impact pH measurements.
 
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lubeck

lubeck

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If, in fact, the pH is accurate at pH 8.5+, then the tank needs more aeration and simple aeration will reduce the pH a lot.

Try this test using inside air:


The Aeration Test

Some of the possible causes of low pH listed above require an effort to diagnose. Problems 3 and 4 are quite common, and here is a way to distinguish them. Remove a cup of tank water and measure its pH. Then aerate it for an hour with an airstone using outside air. Its pH should rise if it is unusually low for the measured alkalinity (Figure 2). Then repeat the same experiment on a new cup of water using inside air. If its pH also rises, then the aquarium’s pH will rise simply with more aeration because it is only the aquarium that contains excess carbon dioxide. If the pH does not rise in the cup (or rises very little) when aerating with indoor air, then that air likely contains excess CO2, and more aeration with that same air will not solve the low pH problem (although aeration with fresher air should). Be careful implementing this test if the outside aeration test results in a large temperature change (more than 5°C or 10°F), because such changes alone impact pH measurements.
I’ll throw the air stone in and Monitor.
 

gbroadbridge

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There’s a diy borax ph standard you could make if there’s a possibility your 10.0 buffer has gone off.
pH 10 buffers typically only last about a month after opening Which is why I use single use sachets for that buffer.

The freshly mixed borax solution is a good sanity check to see if the probe is still okay
 
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lubeck

lubeck

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I recalibrated and the probe is still reading 8.7 at peak. I’m not making any changes as it’s been a month with no ill effects on the corals.
87F04F80-1E05-44CD-82CF-E23F7BEE4A6B.png
 
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Garf

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I recalibrated and probe is still reading 8.7 at peak. I’m not making any changes as it’s been a month with no ill effects on the corals.
Just looked at your build thread and, wow. Increasing aeration will lower your pH, but with the tank you’ve got, dang. Why tick about with it :)

FWIW - if your water isn’t turning a merky white, your good for pH. When it does turn murky it actually corrects itself.
 
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lubeck

lubeck

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Just looked at your build thread and, wow. Increasing aeration will lower your pH, but with the tank you’ve got, dang. Why tick about with it :)

FWIW - if your water isn’t turning a merky white, your good for pH. When it does turn murky it actually corrects itself.
Appreciate you taking a look at the build thread. The tank has really taken off the last three months. It’s maturing nicely.

im going to see if I add the airstone again but it didnt Really do anything.

im reading Randy’s article again to see if I missed anything.
 

Randy Holmes-Farley

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Outside aeration went from 8.35 to 8.40. Not sure what this tells me

It doesn't tell you much at that starting pH. If you can, do it when the pH is peaked.

If the pH is reading 8.7 and does not drop a lot on aeration, then it is likely reading high in error.
 

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