Through advice on this board, I've been adding bleach to my pool for the last year, instead of using 3" tabs. For some reason, the pool did not turn green this winter, perhaps partially that I did not neglect the chlorine level quite as much, and perhaps because I've had an intelliflo VF pump also for the last year, and it keeps the flows up, even when the filter starts to get clogged some. I finally cleaned up the fairly small amount of leaves on the bottom of the pool.
But something strange has been happening. I haven't been adding much chlorine for the past few weeks. (The pool water is sparkling, perhaps the best it has been.) Pool is in the sun most of the day, and is usually covered with a blue bubble solar cover. In fact, I haven't added any chlorine for about the past week, I think. OTO test has been 5.0 or higher. DPD test has been 3 or higher. Gosh maybe my test chemicals are too old, and causing bad results?
So I purchased a TF-100 test kit, with a SpeedStir, and it all arrived today. Still have not added chlorine in awhile. Results from TF-100
FC 5 (OTO)
FC 5.5 FAS-DPD Chlorine Test
CH 580 (I ran it three times with consistent results)
So what happened? Is there some mysterious force, causing me to no longer have to add chlorine? This is twilight zone stuff........