Ok I was not counting the last drop, results are unchanged 21 drops last night, 18 drops this morning. 10.5 to 9.0 FC The water looks spectacular, crystal clear. There are always several (30-40) insects (spiders, rolly polly, worms and earwigs) in the bottom of the pool every day. I vacuum them out every other day. Could I be losing FC to those bugs as well? As far as pH is concerned I test before I add chlorine. Very little aeration....one jet that just breaks the surface. I will try and post a pic.