Have been lurking TFP for several years, just joined the forum. Thanks for great results with TFPC. I mostly try to use bleach, but sometimes add Trichlor tabs when I'm away for a week or so. Pool has looked great all year. A friend was looking after the pool while I was away, noted low (or no) FC with OTO kit and dept adding four 3-inch trichlor tabs about every 5 days. FC wasn't coming up, so he went to pool store where they sold him PhosFree, told him to double-shock (with dichlor).
Yesterday I raised the FC to 20 with bleach; FC was 17 at 2 PM, 11 at 6 PM, and 4 first thing this morning. Latest test results:
CYA 160 (50% dilution method with tap water. Now out of CYA reagent -- more should arrive from TFtestkits next week.)
pH 7.4 (yesterday before I added the chlorine)
Went to local Leslie's looking for chlorine. (Surprised to find them using the Taylor K-2006.) They told me my CYA was 100, tried to sell me Bio-Active CYA reducer or recommended a water replacement. (Phospates - their test - <100 ppb)
Water is clear and sparkling, not sure why the OCLT shows such a drop. Pool water last night and this AM smelled like chlorine (unusual).
Here's my dilemma:
It would cost me about $300 to drain and refill, and there are about 6 weeks left in the season before I do a partial drain below the skimmers to winterize. (My CYA usually drops over the winter. Last complete drain was in 2009, to fix a crack.) Today I added 6.5 lbs Cal hypo 68% (on sale 50 lbs for $140) targeting FC about 25. Frankly, I'm a bit nervous about shooting for FC of 40-50 that the FC/CYA charts recommend, especially with water so clear, and smelling of chlorine already, I'm afraid to use the pool.
What I should do next? Keep the FC between 7-12? Keep the FC as high as I can until it passes the OCLT? Any other ideas?
Thanks, and sorry for such a long first post.