I'm new to TFP, but have been treating my pool for several years. I had a yellow stain on my pool walls, which I identified as iron using ascorbic acid. I decided to treat it with Stain Free (Citric Acid).It required pool chemistry as follows: pH 7.2-7.6, TA 80-120 PPM, CH 200-400 PPM, CYA below 50 PPM, phosphates < 100 PPB, FC =< 1 ppm. I brought my pool chemistry to these requirements and added the Stain Free and turned off the pump for the evening. The stains were gone by morning, and I added Metal free and vacuumed the pool and backwashed as prescribed. I added Polyquat 60 to protect against algae. I also have a CuLator pouch in my skimmer basket. I am trying to bring the FC back up to 1 to 3 ppm, but have added a gallon of Clorox with no effect. The following chemistry was recorded most recently: FC-0.5ppm, pH-7.2, Temp.-82 deg. F, TA-60ppm, CH-275 ppm, CYA-90, CC-0 ppm. The label says not to shock the pool for a week. I am concerned that the low FC will invite algae back into the pool. Should I sit back an relax for a few more days before shocking the pool, and if so, what should I use to shock it?