I try to test it twice a day. I now understand that I want to keep it at a certain level and not yo-yo. I have a cartridge filter and I have been running 24/7. My filter pressure was a bit high (15 psi) I have cleaned it and it was back to 7psi. Today it is a 11 but if I understand correctly I should not clean it to often because if it is a little dirty it will help filter the finer particles. Is this correct? Thanks for the help.