My CYA is at 70, I keep my chlorine around 6 but sometimes up at 11 (swg pool). When I opened this year my filter is letting sand into the pool and the 7 way valve is allowing water to drain when is set to recycle. It is an old Jucazzi Laser 190 With a Praher 7 way valve. My pool is 60,00 liter with a 3/4 hp pump. Could the high chlorine cause problems with the laterals and valve maybe causing the plastic and rubber to become brittle? I'm thinking about replacing it but I'm not sure size sand filter to purchase. I read somewhere that my pump might not move enough water to backwash a large sand filter. I'm OK with a sand filter but am also considering a DE filter. How many years do you get from a DE filter comparing it to a sand filter. Is the water that much clearer with a DE filter to off set the price?