Hi

I have been battling now for a few months trying to sort out my water chemistry.

I use pure R/O DI water, remineralised with Kent R/O Right and pH stable. My problem is I can never seem to attain a pH of 6.8-7.0 with a KH of around 3 degrees. Everytime I reach 3 degrees, the pH ends up close to 8.0!

Presently, I can get the water to about 7.5 with a KH of barely 1 degree. I can bring the pH down in my tanks because I use CO2. It doesn't appear to cause the fish any problems having the new water with a higher pH. The TDS is the same, but I would like to increase the KH to about 3 degrees to be on the safe side to prevent any future pH crashes. I read in a mag the other week someone having a pH of 6.5 and a KH of 6 degrees, this just seems impossible! I am also starting to question the accuracy of my A.P.I KH kit. My pH and TDS are done electronically.

My tank is well planted and blows CO2, below is the water chemistry.


Fresh water Community tank

NH3=0

NO2=0

NO3=10-30mg/L

TDS=200ppm (11 degrees)

KH=0-1 degree

pH=6.8-7.0

PO4=0.5mg/L

Temp=78


All advice welcome.


Cheers