So I have opened my pool for the year and regulated my numbers, but I have a few quick questions. First off, do I need to use the DPD-FAS test for every chlorine reading? I have the regular chlorine test, is that sufficient enough for general chlorine guidelines or should I be using DPD powder every single time? If I test every day I can see where that would be an expense. Also the CYA test seems a bit subjective. Depending on where I am sitting and what light I am looking in the CYA test comes out different. I do it at least twice and average. Does anyone think this? Thanks. Oh and is it better to test in the morning and add chemicals in the morning, or test at night and add at night?