I am new to TFP and really need some help. I am having trouble keeping my FC level up. I thought maybe it was an ammonia problem so even though I didn't have an ammonia test, I began slamming last weekend. I read and did everything recommended in pool school and kept my chlorine level at 20 for 1 1/2 days. After blowing through at least a dozen gallons of 9% liquid pool chlorine and seeing no results, I was disgusted and decided to let the level fall back down to a normal level. Purchased an ammonia test kit Monday and found that isn't the problem. Shocked it again last night just to see what would happen overnight and I dropped from 26 to 16 FC then dropped another 8 throughout the day today. Help!!
FC=8 1/2 (It was 26 last night before bed)