Ph vs Alkalinity

Charterreefer · Feb 12, 2018

I have hit the upper limit as far as being able to raise my dkh in relation to my pH! I have a Korallen 3200 reactor with a second stage too. It's the larger sized reactor. I have a 250 gallon tank. I maintain low nutrients (NO3= ~1.0ppm, PO4= 0.01~0.02ppm). It's stocked with all sps that are apparently demanding a lot of Calcium.
Here's the issue: My pH is a solid 8.0 at a dkh of 7.4- 7.5 (meas at 9:00am). If I raise the dkh to 7.7-7.8 (by increasing my CO2 bubble rate) the pH consistently drops to 7.9 (meas at 9:00am). Ideally I would like to have dkh at 7.7 with a pH of 8-8.1 if at all possible.

Any thought or suggestions would be greatly appreciated.

Cory · Feb 12, 2018

Run your skimmer line outside and use limewater in your top up water.

Randy Holmes-Farley · Feb 12, 2018

Charterreefer said:
I have hit the upper limit as far as being able to raise my dkh in relation to my pH! I have a Korallen 3200 reactor with a second stage too. It's the larger sized reactor. I have a 250 gallon tank. I maintain low nutrients (NO3= ~1.0ppm, PO4= 0.01~0.02ppm). It's stocked with all sps that are apparently demanding a lot of Calcium.
Here's the issue: My pH is a solid 8.0 at a dkh of 7.4- 7.5 (meas at 9:00am). If I raise the dkh to 7.7-7.8 (by increasing my CO2 bubble rate) the pH consistently drops to 7.9 (meas at 9:00am). Ideally I would like to have dkh at 7.7 with a pH of 8-8.1 if at all possible.

Any thought or suggestions would be greatly appreciated.

It is because a reactor adds CO2, and the more alk you deliver, the more CO2 it is delivering to the tank. The low pH is the main drawback to using a CaCO2/CO2 reactor.

That said, a pH of 7.9 is OK.

This has more:

pH And The Reef Aquarium
http://www.reefedition.com/ph-and-the-reef-aquarium/

Charterreefer · Feb 12, 2018

Randy Holmes-Farley said:
It is because a reactor adds CO2, and the more alk you deliver, the more CO2 it is delivering to the tank. The low pH is the main drawback to using a CaCO2/CO2 reactor.

That said, a pH of 7.9 is OK.

This has more:

pH And The Reef Aquarium
http://www.reefedition.com/ph-and-the-reef-aquarium/

Thanks Randy!
I read the article and will start dosing lime water by dripping after lights off until they come back on. I'll have to figure out how much lime water to put in the bucket and drip rate for a 14 hr length. If it works out I could get a dosing pump or something like that.
I am however a bit nervous, I don't want to take a chance that my pH goes too high. I don't want to have a wipe out.

Randy Holmes-Farley · Feb 12, 2018

Charterreefer said:
Thanks Randy!
I read the article and will start dosing lime water by dripping after lights off until they come back on. I'll have to figure out how much lime water to put in the bucket and drip rate for a 14 hr length. If it works out I could get a dosing pump or something like that.
I am however a bit nervous, I don't want to take a chance that my pH goes too high. I don't want to have a wipe out.

It is very unlikely to get too high.