I Calibrate my pH Probe with the One time Use pH solutions. Then I tweak it while it’s sampling the tank water, to what two different pH test come out too. BTW I kept reading about Dosing this and that to keep the pH up. I was having little success, then I started noticing that most talked about high CO2 in our homes. I took an old Air Pump, put a rebuild kit in it that I had. Carefully drilled a hole in it near the coil. Put a piece of 1/4” ridged Air Line tubings Superglue in the hole. Sealed the pump base and cord up with Aquarium Silicone glue. Ran the tubing outside to an old pill bottle layered with Dacron and Aquarium Charcoal, low pH is solved with no extra dosing.
