Help raising PH

[omar jawad]

My PH in my tank ranges from 7.66 to 7.98 and averaging 7.83. It has been this way since I built the tank in July.
I have been able to keep SPS alive but I am not happy with the growth. I don't know if this is a factor or not. My Alk, Calcium and Magnesium are stable and with my dosing system, remain that way.

If the PH is not idle, what are some reasonable ways to increase the PH?

Thank You

 

[Randy Holmes-Farley Verified Community Expert]

Low pH at normal alkalinity is due to elevated carbon dioxide in the water, and that is usually because there is elevated CO2 in your home air.

Ways to raise the pH including bringing in more fresh air (open windows, bringing in an outside air line to a skimmer inlet), removing soem fo the CO2 from the air entering a skimmer (with a CO2 scrubber which has media in it) and removing CO2 from the water (using photosynthetic organisms such as macroalgae, especially lit at night; using limewater (kalkwasser) for calcium and alkalintiy supplementation).

I discuss it in these articles:

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

Low pH: Causes and Cures by Randy Holmes-Farley - Reefkeeping.com
http://reefkeeping.com/issues/2004-09/rhf/index.htm

 

[GainesvilleReef]

From your post I am assuming you are using 2-part for Alk and Ca. You might want to try dosing a saturated kalk solution instead. The effect on ph will depend on how much you have to dose. It essentially removes the CO2 from the tank. However, the CO2 soon returns from the surrounding air. So it's effectiveness is based on the rate kalk is added versus the rate the CO2 returns. A tank with low demand for Alk and Ca will see little benefit at first. But, as the demand increases and you add more and more kalk the effect will be greater. The upper limit, as to how much you can add, is determined by how much top off water you add. Before switching to kalk I had pH ranging from 7.8 to 8.0. Now my ph is steady from 8.15 to 8.25. Due to evaporation limits I have had to add 2 part on top of my kalk dosing so don't undo you Alk and Ca 2 part equipment if you choose this approach. If you are currently dosing mag with your dosing pumps I would use that for kalk. I bolus dose mag about every 6 months and easily keep it between 1300 and 1350. I have also found, as Randy mentioned above, that macro algae helps a lot as well. Also, as Randy said, the root cause is ambient air. If there is something simple that you can do easily to improve the CO2 levels, do that first. Good luck.