dirt blowing out returns on Starite Cartridge Filter

[jwilliamson]

I am hoping someone can help me troubleshoot this problem. I have a Pentair Starite 3 S7m120 cartridge filter. I've noticed my water has been getting cloudy over the last several weeks and seemed to be getting worse. My cartridge filters were about 6 years old and bands were breaking so I replaced them (with Pentair OEM brand) but the problem continued. I've increased my pump runtime to 24 hours at full RPM over several days and it didnt clear up. Check my chemicals (posted below) and everything looked good. I noticed that when I shut my pump off that I could see some dirty water drifting out of all my returns (slowly). When I start up my pump it will blow dirty water out for about 20-30 seconds. I put a sock over one of the returns to catch it and it is gritty like dirt and sand, not slimy like algae. I opened up my filter and looked for anything that would allow the water to bypass the filter. I checked that the cartridge filters are position correctly on the inlets and set firmly in place, checked the o-rings around the inlets, checked the air bleeder tube and filter. Even though the filters are new I went through and checked them thoroughly for tears, holes, rips or cracks in the caps. I am wondering if I have a hole or crack that I cant see or feel in the elbow and bulkhead assembly (picture attached) that is allowing unfiltered water to return?

FC 5
CC 0
PH 7.7
TA 90
CYA 27
CALCIUM 223

 

[Newdude]

Hew J and Welcome !!!

Is the cartridge snug and level ? They can be a bit fussy to line up right and seat properly.

Did you apply that sealant / caulk or was it always there ? The newer S8 models are one piece molded but I can see yours being factory with the 2 pieces. So it's either the cartridge sitting crooked or that mating surface most likely.

 

[jwilliamson]

Hew J and Welcome !!!

Is the cartridge snug and level ? They can be a bit fussy to line up right and seat properly.

Did you apply that sealant / caulk or was it always there ? The newer S8 models are one piece molded but I can see yours being factory with the 2 pieces. So it's wither the cartridge sitting crooked or that mating surface most likely.

That sealent was always there. Which makes me wonder if it was put there long before I owned the pool (more than 15 years) to fix a leak and is breaking down. The pool filter itself is more than 15 years old. I checked that the filters are sitting properly because that was my first thought. I also checked the o-rings around the seating. The filters do fit snug and level. That is one of the reasons I bought the Pentair OEM filters when I first started noticing my water was cloudy and decided to replace a 6 year old set rather than buying a cheap brand. The thing that has me worried it's something around the elbow assembly is, in 15 years, I have never seen dirty water come out of the returns when the filter is draining and for the first 30 seconds when the pump is turned back on. Other than filter media not sitting correctly, tears or holes in the filters I cant see how the filter is being bypassed. Is there another part I havent checked that I may be overlooking? Is there a way to confirm or eliminate the elbow/bulkhead assembly as the problem?

 

[Newdude]

Is there a way to confirm or eliminate the elbow/bulkhead assembly as the problem?

Gorilla tape maybe because the suction will only help seal it?

See if the bulkhead is jiggly when you're in there. I imagine it would need a decent sized gap to let that much crud through.

Did it happen immediately after changing the filter ? You should have started with fresh water in the tank also, so crud would take time to accumulate, to then dump in the pool.

 

[jwilliamson]

Gorilla tape maybe because the suction will only help seal it?

See if the bulkhead is jiggly when you're in there. I imagine it would need a decent sized gap to let that much crud through.

Did it happen immediately after changing the filter ? You should have started with fresh water in the tank also, so crud would take time to accumulate, to then dump in the pool.

The bulkhead isnt jiggly for sure. In fact, I am worried that with the sealent on there. I may not be able to get the dang thing out to replace it if turns out to be the problem without replacing the entire lower half of the filter housing. The water started getting cloudy before I replaced the filters. My water is normally crystal clear..when it starts getting hazy, I will check double check the pressure and if it's 10 PSI above starting pressure then it's time to clean the cartridges. About once a season cleaning does it and then it is back to normal. But this set of filters was at least six years old, bands were breaking and I couldnt get them as clean as it used to be so I decided to replace them. So the problem started before I replaced them but the water hasnt cleared up after and has slowly gotten worse over the last 3 weeks. My PSI on the new set is normal startup pressure (about 15 PSI) and has stayed there ever since. The water in the tank is definetely dirty (today for sure). I've drained some of the water out of the drain valve into a bucket with the pump off (filter still completely assembled and closed) and you can see sand/dirt in it. But even if the water in the filter tank was dirty, doesnt all the water have go through the filters before it can return even if it's not under pressure? And once I turn the pump on and it primes, I still dont see how the dirty water can get to the returns unless it is bypassing the filter somehow?

 

[Newdude]

But even if the water in the filter tank was dirty, doesnt all the water have go through the filters before it can return even if it's not under pressure?

Yes. The tank water is the dirty side. Then it goes through the filter and out the pipe.

And once I turn the pump on and it primes, I still dont see how the dirty water can get to the returns unless it is bypassing the filter somehow?

Without an MPV valve leftover from an old sand or DE filter, cartridge filters don't have a recirculation option. So if dirty water is getting past the new filter, it's getting through that bulkhead.

 

[jwilliamson]

Yes. The tank water is the dirty side. Then it goes through the filter and out the pipe.

Without an MPV valve leftover from an old sand or DE filter, cartridge filters don't have a recirculation option. So if dirty water is getting past the new filter, it's getting through that bulkhead.

No MPV valve. Just a diverter to control main drain/skimmer suction. The only other thing I can think of is some of the particulates are too small to be filtered. I've used some clarifier and the pool will improve noticeably for a short time (2-3 days) but I think that is just masking the problem. Before this problem I've had to use a clarifer twice in 15 years. I've even considered adding some cellulose to the new filters to see if that would help. I've got sparkleypoolitis so not being able to pinpoint where the problem lies is driving me nuts.

 

[Newdude]

The filter gets down to 10 / 25,400 of an inch. Then the crud that it traps, traps even smaller crud.

It was fair to wonder about old filters with broken bands. But that's not the problem now.

 

[jwilliamson]

The filter gets down to 10 / 25,400 of an inch. Then the crud that it traps, traps even smaller crud.

It was fair to wonder about old filters with broken bands. But that's not the problem now.

Yeah. If it's the filter media, then I must have gotten at least one bad filter in the set brand new from Pentair. At least part of the water is being filtered because when the dirt blows back into the pool, the water will become less cloudy (but never clear) after a few days until I shut the pump down again and then the process starts over again.I am going to close in a few weeks. If I cant figure it out before then, I am going to buy a elbow/bulkhead assembly ($80-$90) and try to replace it right before I close. My only fear is that sealent that is on there is going to cause me to crack the housing getting the old one off. I guess if it does I will be spending the $1500 for a new one over the winter.

 

[jwilliamson]

I am not sure if this has happened to other people but I think I got a bad filter from Pentair. I noticed there was glue between some of the pleats , and just a poor job of gluing the bands in general, and one of the bands had started to fray after just a couple of weeks. After doing some more troubleshooting with a spare set of filters that I got my hands on, the pool has cleared up about 90% (still monitoring) and I couldnt reproduce the return problem any longer. I took the 200 sq foot filter back to the pool store and they replaced it. Swapped the old new 100sq foot filter and the new new 200 fq foot filter out with the spare set I was able to borrow and I cant reproduce the return problem and the water continues to get clearer. So I dont think the elbow assembly was the problem, it was something with larger of the new filters, even though I still could never find any holes or tears in it. It's hard to inspect every bit of a 200sq foot filter so it could have just been missed. I am dissapointed at Pentairs lack of quality control. This is my third new set over the last 15-17 years, but first one since the pandemic. Maybe they arent worth the premium price anymore.

 

[Newdude]

Glad it worked out. It was fair of us to assume the new filters were Ok. But quality control of any goods whatsoever is a thing of the past. I returned a set of Pentair filters because they gave me the wrong ones, but the glue job on them was terrible like you mention. Parts of the accordion were oval, not round and the depth of thr glue ranged from almost none to over an inch down the accordion. I was happy to not have to find out if they'd work.

 

[jwilliamson]

Thanks for your help. Not sure how often this happens but for anyone reading this thread with a similar problem. Make sure you check the stores return policy before you buy new filters. I was lucky enough to find a store that would let me return them after they were used. Online store wouldnt do it and Pentair wont honor warranty unless they "are professionally installed" and most of us here do maintenance ourselves. I have a good relationship with the manager at the local franchise and she did a warranty exchange for me. If not for that, I would have been out almost $450.