Low pH, High Alkalinity

[Stub]

I have the same problem, low pH (7.8) and high Alk (280 ppm). Stopped dosing Kalk and after a couple of months dropped to 217 and leveled out there. Now for C02 - the most direct measurement I could find was to take a sample of my water (jam jar size) outside and aerate with a small air pump for 1 hr and measure the pH. Raised pH 0.1 and I believe this is consistent with what I am seeing in my system. I have a large system with about 300 gal capacity spread over 4 linked tanks including the sump (partially filled 125 gal tank). I have a considerable aeration capacity in the system, including a 2 cubic foot bio tower, 4 ft skimmer and heavy surface aeration from water movement (also ran an airline to outside the house). Main tank (180 gal) has been in operation for 18 years. Outside air is pumped into the house year round via the HVAC system. One other aspect of my system - I am running a 2 stage C02 calcium reactor and the second stage should be dealing with most excess C02 and this is consistent with my outside air experiment mentioned above. I cannot move the pH beyond 8 for short periods and need some opinions.

Thanks

 

[lapin]

Is there a reason a PH of 7.8 will not work for you.

 

[Stub]

I have many corals and I want to improve their growth rate. Additionally, at 7.8 I feel that this is too close to a bigger problem at 7.7 or worse. I am also frustrated by the cause - not understanding why. Can you offer an opinionÉ

Thanks