Hi, I have a 3 year old Pentair FNS+4800 DE filter. I've had trouble with clamp issues, broke one overtightening it, learned a lot. Today, the clamp seems fine but I have o-ring problems. After running for a few hours the o-ring pops out of its channel and water flies in all directions. The lid does not blow off because the clamp holds. The clamp also catches the o-ring. so far I have backwashed and replaced the DE, thoroughly cleaned the channel where the o-ring goes on both top and bottom parts, replaced the o-ring with a new one in manufacturer's packaging, lubricated the o-ring being careful not to stretch it, made sure all returns are open and operative. Still no help. The clamp appears to be on all the way, plenty of hammering with a rubber mallet, tightened as directed until the spring coils touch each other. bolt makes screaming noises for the last couple of turns. If you don't have any suggestions I might have to convert my pool to be a big garden planter. Not really, but I am desperate.