I am new to this forum, but have been reading recommendations from TFP for about a week. I have read through the "Pool School" twice. We have had our pool for 10 years with very few water problems, but I have decided to educate myself beyond the standard OTO/ph test. In fact, I just received my TF-100 test kit today. I was finally prompted to get serious about "managing" my pool myself because for the past two years I am using more and more chlorine. I will post that message next.