With a pH of 6.9 and KH of 9.0 it looks like my fish should be stressing since CO2 should be 33.991. Yet they all look very content swimming at all levels of the tank. I am measuring the CO2 with a Milwaukee ph 600 meter and KH with an Aquarium Pharmaceuticals test kit. I also checked both with one of the strips and got pretty much the same readings. How does one reduce the KH?