Filter Leaking


Bronze Supporter
Oct 8, 2018
Plano, TX
Good morning. Looking for advice.

I just got finished with a SLAM last Tuesday. Since then I have had to re-fill my pool with water almost everyday, at least an inch. I started investigating at the equipment pad and noticed water leaking from the back joint of the clamp keeping the top and bottom together. It's a fairly consistent leak but doesn't seem so bad as to drain an inch or more of water everyday. I did a full filter cleaning less than 3 weeks ago and it wasn't leaking for sure before I started the SLAM.

1. Is it likely that there is something else wrong to lose so much water? I'm not seeing bubbling anywhere around the pool, or water dripping from any other equipment.

2. The gasket was in good shape and lubed up when I cleaned the filter a few weeks ago. Is it fairly common for something like this to happen when you are running the pool as long as I did for the SLAM (~5 days straight)? I also tightened down the clamp a little more, but that didn't stop the leak. The pressure is at 18 today and it's been in normal range since my last backwash (8 days ago).

any suggestions before I take the filter apart again and replace the gasket?

Any help is always appreciated. love this site!


Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
Laughlin, NV
Pool Size
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
An inch a day of water is pretty extreme (I would suspect a couple hundred gallons per day).

Pool School - Leak Detection

You do need to disassemble the filter and be sure to use Pool Lube on the gasket after a thorough cleaning of the gasket and all mating surfaces.

Take care.


Gold Supporter
TFP Guide
Nov 12, 2017
Central California
Pool Size
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
Marty beat me to it (he usually does)!

O-rings... I learned about them during my scuba diving days.

Once the filter is disassembled, remove the o-ring completely. Set it aside on a clean surface. Do your filter maintenance stuff, then go wash your hands. Wipe the ring off with a clean, lint-free cloth. Use the same cloth to thoroughly wipe clean both halves of the filter housing where the o-ring seats. This is usually overlooked. While wiping the housing, look for any nicks or other deformities where the o-ring touches. A tiny particle or slice on either surface can cause a leak. Remember, the filter is under decent pressure when the pump is running, so it doesn't take much to affect the o-ring's seal. Once the housing is clean, pick up the o-ring, wipe it down again, then apply a very light coating of lubricant. The lube does not provide any sealing. More isn't better. It only allows the ring to move easily while it is being compressed so that it doesn't get warped or pinched. There should be no globs or streaks of lube on the ring. Apply only just enough to make the ring look wet (like Armor-Alling your tires). I apply lube to my forefinger, then rub my thumb in it. I then pinch the ring between those two fingers and pull the ring through with my other hand. A fatter ring requires a bit of adjusting of the fingers. I'm applying pressure with my fingers to help apply just a thin coat, but I'm also tensioning the ring slightly. By doing so, I hope to expose any cracks or nicks while I pull. I'm feeling for either with my fingers, while looking closely at the same time. I usually go around at least a couple times. Then carefully seat the ring in the lower half of the housing without allowing it to touch anything else. Reassemble the housing and tighten the ring. Your filter's owner manual should specify how to tighten the ring properly. Go with that.

Do not use petroleum-based products like vaseline. This is what I use: Magic Lube II Silicone Lubricant, Sealant for Pool Valves O Rings 1 oz # 650: Kitchen Dining

Safety tip: be sure to turn off all the breakers to the pool equipment while servicing your filter. You do not want the pump coming on during any stage of the process. It can be especially dangerous while removing or replacing the filter's clamping ring.

Once you've solved the leaking filter housing, then you can perform a proper bucket test (leak test), as described in the link Marty gave you (here).
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