I have a Pentair CCP320 Cartridge Filter system and recently had to replace the large o-ring that sits between the top and bottom halves because the old one got stretched and wouldn't say in place for clamping.
After replacement, I've been unable to get it to seal under the high speed pressure. I get copious amounts of spray around the metal band clamp. It seems to seal well enough for low speed running, but I'd obviously like it to work for both. Even though it looks similar to what I had before, it seems to me like the new o-ring isn't thick enough because it looks like the top and bottom halves end up almost touching each other. I've tightened the metal clamp more than I previously had to, to the point I'm afraid to go more. The old o-ring had actually developed a flat side. I'm assuming it was originally as round as the one I just bought.
This is the o-ring I bought: Pentair 39010200 Tank Clamp O-Ring Replacement Pool and Spa Filter
I did lube the o-ring with magic lube, but that hasn't helped.
I checked for cracks in the lid and didn't spot any. As I'm typing this, I'm not sure if I checked the bottom for cracks, so I'll have to do that. Any other thoughts if that's not it?