I just bought a house with a above ground pool. The pool measures 16 by 11 and it is 4 feet deep. The PH is 6.8 but no matter what I do I cannot get the chlorine up past a zero reading. The pool store says my CYA level is low, the pool is clear, I even used phosphate remover. I again shocked the pool last night, and again the chlorine reading is zero this morning. I really dont know what to do, after reading this site I dont trust the pool store. Should I put bleach into the pool? If so, how much???