Several people responded to my pH/CO2 problem. The overwhelming response was that my CO2 test kit was wrong. So I tested it by taking some of my "70 ppm" water and aerating it for about an hour with an air stone. The results: the aerated water measured out at 40 ppm CO2. So I'm chucking my Red Sea CO2 kit and just going back to using the chart. Thanks for all the input. Craig