PENTAIR 4000 series cracking

Rick Irons

New member
Aug 23, 2020
I'm on my second Pentair 4000 filter. Both have developed cracks in the bottom housing just down from the clamp ring. Are they prone to cracking or is there something I'm doing wrong? Not leaking yet - it's an exterior crack. The only thing I can think of is there is very little flex in the system so when it pressures up you can hear it getting "tight".

Also, if there is a better filter, I'd love to know. I have no experiece with Hayward or cartridge filters.



Gold Supporter
TFP Guide
Jun 16, 2019
Hey Rick !!! If you want beefy check out Pentair/ Sta-Rite system 3 filters. They have sand, DE and cartridge. The housing is 1/4-1/2 inch thick and all but indestructible. They are all belt free which seems to be the biggest complaint of any of those style filters. The System 3 uses 8 equally as indestructible clamps that have hand knobs for tool free maintenance.


Gold Supporter
May 16, 2010
Chapel Hill, NC
Call Pentair and let them know about your problem. Hayward had issues with some of their filter tanks a few years back - there's no reason to believe it couldn't happen to Pentair (they probably all come from the same factory in China).
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