Should I worry about pH of 8.5?

Dom · May 11, 2020

A few months ago, I had an issue with my Nems not fully inflating. The cause was low ALK, sitting at about 4.5-5 range.

I began using Kent Marine dKH SuperBuffer and over time, have my ALK in the 8-9 range. But, my pH is running in the 8.5 range since I started supplementing buffer.

Should I be concerned?

Neoalchemist · May 11, 2020

Nothing to worry about until above 8.6.
If that is a ph buffer,Use an alkalinity supplement in the future. Ph buffers are generally a bad idea in any tank.

CCauthers · May 11, 2020

It depends, how is everything doing right now in the tank? If everything is doing well, then I wouldn't change it

Dom · May 11, 2020

Neoalchemist said:
Nothing to worry about until above 8.6.
If that is a ph buffer,Use an alkalinity supplement in the future. Ph buffers are generally a bad idea in any tank.

It is a pH buffer. I have also tried Red Sea Foundation B. How do you recommend I supplement ALK?

Dom · May 11, 2020

CCauthers said:
It depends, how is everything doing right now in the tank? If everything is doing well, then I wouldn't change it

The issue was with the Nems, and they have bounced back nicely. No other apparent issues at this time. But as I said, my pH has been rising steadily and I would like to deal with it before it gets too high.

Randy Holmes-Farley · May 12, 2020

Dom said:
The issue was with the Nems, and they have bounced back nicely. No other apparent issues at this time. But as I said, my pH has been rising steadily and I would like to deal with it before it gets too high.

pH 8.5 is fine, and pH never rises out of control unless you overdose high pH additives (which the Kent product is not) or the alkalinity is far higher than you measured. Artificial rock made from cement and not fully cured can raise pH and alkalinity.

I would not worry about high pH, but pH is determined mathematically by the alkalinity and the CO2 level in the water. If the pH is too high for the alkalinity, more aeration will bring the pH back to normal.

Dom · May 12, 2020

Randy Holmes-Farley said:
pH 8.5 is fine, and pH never rises out of control unless you overdose high pH additives (which the Kent product is not) or the alkalinity is far higher than you measured. Artificial rock made from cement and not fully cured can raise pH and alkalinity.

I would not worry about high pH, but pH is determined mathematically by the alkalinity and the CO2 level in the water. If the pH is too high for the alkalinity, more aeration will bring the pH back to normal.

Thank you. I run a protein skimmer 24/7, have good surface agitation and a cover made from egg crate. I will add an airstone to the sump and see what impact this has.

Dr. Jim · May 12, 2020

Randy Holmes-Farley said:
If the pH is too high for the alkalinity, more aeration will bring the pH back to normal.

@Randy Holmes-Farley Is it possible that when the pH is 8.3-8.5, if the air used for aeration is "outside" air that is CO2 scrubbed, then the pH can continue to rise? (In other words, is it possible that a CO2 scrubber can lower the CO2 in the air below the CO2 level in the water when the pH is 8.3-8.5)?
Thank you!

kevin_e · May 12, 2020

Dr. Jim said:
@Randy Holmes-Farley Is it possible that when the pH is 8.3-8.5, if the air used for aeration is "outside" air that is CO2 scrubbed, then the pH can continue to rise? (In other words, is it possible that a CO2 scrubber can lower the CO2 in the air below the CO2 level in the water when the pH is 8.3-8.5)?
Thank you!

Yes. My skimmer is fed by outside air that passes through a CO2 scrubber. My pH routinely gets near 8.5 when we are not home. It averages 8.2 and typically runs anywhere from 8.05-8.30. Keep in mind this is during the covid period too. When we both start back to work, pH may get closer to 8.6 at which point I may need to change some things.

Randy Holmes-Farley · May 12, 2020

Dr. Jim said:
@Randy Holmes-Farley Is it possible that when the pH is 8.3-8.5, if the air used for aeration is "outside" air that is CO2 scrubbed, then the pH can continue to rise? (In other words, is it possible that a CO2 scrubber can lower the CO2 in the air below the CO2 level in the water when the pH is 8.3-8.5)?
Thank you!

Sure, removing CO2 can raise the pH and depending on the relative aeration at the tank top and the scrubbed air in a skimmer, it might get higher than pH 8.5.

Dr. Jim · May 12, 2020

Randy Holmes-Farley said:
Sure, removing CO2 can raise the pH and depending on the relative aeration at the tank top and the scrubbed air in a skimmer, it might get higher than pH 8.5.

If "outside air" can raise the pH above my desired pH of 8.3, then the two options I have (to keep the pH down to 8.3) would be:

A) Use a solenoid to switch from "outside air" to room air (for the skimmer), or
B) Use the Controller to shut off the skimmer when the pH reaches 8.3.

I'm thinking that with "B" the problem might be that the pH may continue to rise due to photosynthesis during the day, (even with the skimmer shut off). So, perhaps the better solution would be "A" (to pump in CO2-laden room air as needed to keep pH down to 8.3).
Would you agree?
Thanks again.

Randy Holmes-Farley · May 12, 2020

Dr. Jim said:
If "outside air" can raise the pH above my desired pH of 8.3, then the two options I have (to keep the pH down to 8.3) would be:

A) Use a solenoid to switch from "outside air" to room air (for the skimmer), or
B) Use the Controller to shut off the skimmer when the pH reaches 8.3.

I'm thinking that with "B" the problem might be that the pH may continue to rise due to photosynthesis during the day, (even with the skimmer shut off). So, perhaps the better solution would be "A" (to pump in CO2-laden room air as needed to keep pH down to 8.3).
Would you agree?
Thanks again.

outside air will not raise pH above 8.3 unless you run it through a CO2 scrubber, or if the alkalinity is pretty high.

blasterman · May 13, 2020

A pH of 8.5 is tough if not impossible to hit unless you are dosing calcium hydroxide or have some pretty heavy macros sucking all the CO2 out. Just blowing outside air in your tank wont do this because outside air has plenty of CO2 in it.

When I see a claim of 8.5 or higher and kalk/macros arent in use I seriously doubt the test kit.

Alk additives dont have much affect on pH. Soda ash will raise pH, but I dont think it's in use here.