Which is a better PH situation…?

BAMatter · Feb 5, 2023

Between dosing kalk, and running a CO2 scrubber, my PH swings from around 8.2-8.3, and sometimes as high as 8.3-8.4 daily. Wondering which situation is ideal, allowing the higher PH happen with a lower PH bottom, or pegging PH at a lower average, but creating PH stability?

If I’m not making sense (likely) which would be better?

1) no intervention and allowing a swing of 8.2 to as high as 8.4

2) utilizing a solenoid on my scrubber to peg PH at 8.2 +/-

Randy Holmes-Farley · Feb 5, 2023

It's a tricky question without much data, but at least one study said corals grow faster with a higher peak than a steady pH that falls in between the peak and trough of the varying one.

I pick number 1.

Fish Styx · Feb 5, 2023

If the swings aren't terribly wild (i.e rapid and frequent) neither should be too detrimental to your system. That being said, I agree that the first option is better.

BAMatter · Feb 5, 2023

Randy Holmes-Farley said:
It's a tricky question without much data, but at least one study said corals grow faster with a higher peak than a steady pH that falls in between the peak and trough of the varying one.

I pick number 1.

Interesting… thank you.

Is anything to be said that any figure over 8.3 is “wasted”, meaning any benefit to limiting the ceiling to 8.3, other than allowing scrubber media to last longer? So let her rip 8.2-8.3 instead of 8.2-8.4?

BAMatter · Feb 5, 2023

Fish Styx said:
If the swings aren't terribly wild (i.e rapid and frequent) neither should be too detrimental to your system. That being said, I agree that the first option is better.

Pretty standard chart I’d say, swings around .1-.16. However I feel (could be coincidental) when swings were .05+-/ things looked better in terms of polyp extension. Again, could just be me looking for a non-existent plus…

Screwgunner · Feb 5, 2023

As far as I am concerned you have great numbers no matter what! It seems to me there is always a swing from daylight to darkness. I run ATS and mine stays at 8 . But I agree with Randy!

Fish Styx · Feb 5, 2023

BAMatter said:
Pretty standard chart I’d say, swings around .1-.16. However I feel (could be coincidental) when swings were .05+-/ things looked better in terms of polyp extension. Again, could just be me looking for a non-existent plus…

I would defer to Randy's expertise here, but IMO, this looks perfectly fine and I wouldn't be terribly concerned. IME, I see better growth and polyp extension with ph around 8.3-8.4. My system can fluctuate as high as 8.5 at times with no I'll effect. That being said, when I dip below 8.2 I notice things get a bit "grumpy", so to speak. While 8.4 is at the higher end of "normal", "normal" is subjective to individual tanks and it depends on your system. Continue to observe what works best for your tank and target accordingly.

Screwgunner · Feb 5, 2023

Well it says to try and keep your ph as stable as possible so if 2 works in that regard then 2 it is.

BAMatter · Feb 5, 2023

Screwgunner said:
Well it says to try and keep your ph as stable as possible so if 2 works in that regard then 2 it is.

I may experiment to see how PH stability at sub 8.3 works out. We will see… trying to observe and take mental notes to how corals looks at varied PH levels!

Randy Holmes-Farley · Feb 5, 2023

BAMatter said:
Interesting… thank you.

Is anything to be said that any figure over 8.3 is “wasted”, meaning any benefit to limiting the ceiling to 8.3, other than allowing scrubber media to last longer? So let her rip 8.2-8.3 instead of 8.2-8.4?

I do not think there is evidence of that in terms of corals.

Risks of precipitating calcium carbonate to an excessive degree rise as ph rises, however.

Randy Holmes-Farley · Feb 5, 2023

BAMatter said:
I may experiment to see how PH stability at sub 8.3 works out. We will see… trying to observe and take mental notes to how corals looks at varied PH levels!

You may find this thread interesting:

Alkalinity stability? pH stability? Are they even different?

It is currently the dogma of the reef aquarium hobby to say that alkalinity stability is very important for SPS corals, and that pH is not. Often, the very idea of someone trying to optimize pH is called “chasing numbers” as if that statement by itself shows it to be foolish. Since I have...

www.reef2reef.com

X-37B · Feb 5, 2023

Interestimg as my ph fluctuates between 7.8-8.2 depending on time of day.
I can open the window and it will be 8.3 for as long as its open.

I have never had an issue with these numbers.

If I remember correctly, as my mind is not as sharp as it was at one point.

Biological activity, photosynthesis, causes pH to increase during the day and respiration causes pH to decrease at night.
So a ph swing is a natural part of the reefs cycle.

Did I get this right, lol.

Randy Holmes-Farley · Feb 5, 2023

90's reefer said:
Interestimg as my ph fluctuates between 7.8-8.2 depending on time of day.
I can open the window and it will be 8.3 for as long as its open.

I have never had an issue with these numbers.

If I remember correctly, as my mind is not as sharp as it was at one point.

Biological activity, photosynthesis, causes pH to increase during the day and respiration causes pH to decrease at night.
So a ph swing is a natural part of the reefs cycle.

Did I get this right, lol.

Yes.

Fish Styx · Feb 5, 2023

90's reefer said:
Interestimg as my ph fluctuates between 7.8-8.2 depending on time of day.
I can open the window and it will be 8.3 for as long as its open.

I have never had an issue with these numbers.

If I remember correctly, as my mind is not as sharp as it was at one point.

Biological activity, photosynthesis, causes pH to increase during the day and respiration causes pH to decrease at night.
So a ph swing is a natural part of the reefs cycle.

Did I get this right, lol.

Yup. Photosynthesis reduces CO2 in the water column and increases O2. That process raises PH. CO2 + H20 = Carbonic acid. So, when photosynthesis stops, i.e. lights out, CO2 raises in the tank thereby lowering the PH. Swings are natural in our smaller "oceans". We can minimize these by running refugia on reverse light cycles, dosing Kalk, or through the use of buffering agents. However, you will still see swings- just not as dramatic.