I've got a tank with the "rising pH". Here is the current parameters:
* low light tank of moss, bare bottom lots of driftwood, peat and indian almond leaves
* 0 nitrate, nitrite, ammonia
* 80 TDS
* 2 KH
* 10-12 GH (API kit wasnt that clear)
* 3-4 hrs of minimal CO2 injection a day to lower pH
about 2 weeks ago the same 3-4 of CO2 can lower the pH to 6.6; when CO2 is off, pH rises all the way to 7.4
over time, the maximum i can lower the pH is 7.0 [this is with even increased 12 hrs of CO2 injection]. when CO2 is off, pH rises all the way to 7.5 and 7.6
there has been no water change during this period. currently there are CRS residents in the tank.
what is going on over time?
the plan will be to slowly replace the water with RO water. another question is - what is the best way of doing so while adding buffer of salty shrimp mineral? so far the strategy has been to put pure RO water to bring down the TDS.