The pool I was working on getting algae free is doing great, I had to tweak a few levels but the Cl is disappearing! The last 2 times I checked the pool with a OTO kit, it barely registered. I use a Taylor FAS-DPD to verify the HTH kit, and there is between .5-1 ppm of free Cl and zero combined. The owner is adding 1/3-1/2 gallon of 6% bleach daily - but I don't think it's enough for a 17K gallon pool. I just added in 1lb of 73% cal hypo and a cup of 54% cal hypo resulting in a free Cl of 7.5 per FAS-DPD test. The CYA level was at 60 last week but we added water in the pool, and now CYA tests at 40.

The pool's in the sun for most of the day, and so I'm wondering what to do either a) more bleach or b) supplement the bleach with a HTH skimmer tab to keep the free Cl a bit more stable.