DE getting into pool

cesmode

Well-known member
Jun 9, 2017
55
Hackettstown
Hi,
I posted this issue several days ago and didnt receive a lot of help so Im posting again.

Im getting DE shot into my pool WHILE the pump is running. The pool and all of the equipment is 3 years old. Pentair FNS Plus 48 filter. Inground vinyl liner.

This is what Ive done to troubleshoot:
  1. Pulled out and inspected each individual grid. There was one grid with a cracked rib that I replaced with a new grid. I looked at all ends, corners, both sides of all grids. I did not see any rips or tears.
  2. Pulled out the manifold and inspected for cracks/hair line cracks.
  3. Replaced the Standup Pipe o-ring and added lube.
  4. Brought the filter grids and manifold to two pool stores for additional 'well trained' eyes. Three pool store guys inspected them. They said my grids look near perfect. One guy said that the grids (pentair) looked like they might have been glued together at the seams on the bottom in addition to being sewn together. The glue in spots is being undone, but it is still sewen together. One guy said that the manifold has a tiny hairline crack but it doesnt go all the way through and looks good.
  5. Replaced the air bleeder tube that plugs into the top of the manifold.
  6. Lubed up the filter waiste band o-ring and removed debris for a much better seal.
  7. Lubed up the pump basket o-ring for a much better seal.
  8. Ensured that the manifold is snug on the standup pipe as well as on the grids themselves covering the cloth (even tried to pull the cloth up the center plastic spine piece that goes into the manifold).
  9. Cleaned up the filter completely (even the bottom manifold that everything sits on). The filter and its elements were spotless.
  10. Unscrewed the Multiport Valve. Spider gasket looked good.
  11. Checked all chems via taylor test kit, all good.
I just called one of the guys that helped install the pool 3+ yrs ago and he joked that hes not sure he wants to come out and take a look because of how meticulous Ive been with troubleshooting.

To vacuum up the DE, Ive been using a combination of the pool bot, vacuum to filter, and vacuum to waste (this is tough because I lose so much water so fast when I do so).

If anyone has any other ideas...

Im about to drop $100-150 on all new grids plus $90 for a new manifold just to be sure that it isn't the grids or manifold. And if replacing all the grids and manifold doesnt fix it...Im literally at a loss and scared that the issue may be under ground or something.
 

TBSNPS

Silver Supporter
Jun 2, 2019
64
Sacramento,Ca.
I've the same filter as you. My manifold had a crack by the vent that I was able to repair. It was easy to see.I did some research and found that many have problems with the Pentair manifold. On Amazon there is a non Pentair replacement manifold that buyers are happy with at around 60 dollars.
I would have a hard time replacing good parts, problem is you can not actually see what is going on inside the filter. Not much help here, If you proceed, I probably would replace the manifold first and see if that corrects the problem, if not then spring for the grids, BTW you can just buy the cloth bags if the plastic grids are not broken. i purchased some aftermarket bags a few years ago and they have worked out fine.
Also I would closely inspect all the plastic pipes for hairline cracks, problem is with no pressure applied cracks are difficult to spot, but as soon as pressure is applied the pipe swells and there you have your leak. Sounds like you have a unique problem. Let us know what you find as the culprit.
 

cesmode

Well-known member
Jun 9, 2017
55
Hackettstown
I ordered a replacement manifold (been dancing around replacing the manifold and all grids, figured I would start with the manifold). Even though I dont see any cracks (there is a hairline but not all the way through the plastic).
 

Texas Splash

Mod Squad
TFP Expert
LifeTime Supporter
Have to ask ... DE while pump is running. Is it continuous or only a burst at start-up?

It does sound as though you've looked at just about eveyrthing we might throw at you. That hairline crack is probably the unknown variable. Even though it doesn't appear to go all the way through, we know those filters create a lot of pressure while in operation. Can't help but wonder if that may be the issue. Something else not noted but figured good to ask ..... you are using pool DE right? Not food grade?
 

cesmode

Well-known member
Jun 9, 2017
55
Hackettstown
Hi,
I replaced the manifold and air bleeder. Same issue.

Someone told me to throw some two part epoxy where the standup pipe meets the black tube that leads out of the filter to returns, so I did that. He said hes heard so many complaints with my filter specifically and this fixed the issue. So, thats done.

While the grids were out, my wife and I set down, again, and inspected each individual grid (took all grids off the manifold).

One interesting thing, yesterday when I went to open the filter top to apply the epoxy, I didnt backwash...I drained some air and then removed the drain plug. Milky water came out. Filter grids look like NOTHING was on them at all as if I just hosed them down. There was a pile of DE on the bottom manifold.. So I thought maybe the DE isnt even attaching to the grids. Took the grids out and I currently have them soaking in " soak and spa" degreaser of sorts to remove oils and dirt from the grids/cloth themselves. I did also buy a jug of muriatic acid, but I only want to use that as a last resort. i might just take the grids out of the soak tomorrow, hose them down, put them back in and see how it goes without the acid wash.

Thoughts?

Also, the pentair spider gasket in the multiport valve has a slight tear in it. I was about to replace that but any pool store guy I talk to says that wouldnt impact it one bit.
 

cesmode

Well-known member
Jun 9, 2017
55
Hackettstown
Sorry, to answer your questions:
I "think" I see it at start up through the returns...its sometimes difficult to tell the difference between tiny air bubbles and DE...but I have definitely seen it at start up at times. Lasts 5-20 seconds maybe and then I dont see it anymore. It builds up over time, 1-2-3 hours later I see it increase in the corners incrementally over time.

Wierd, and I know Im probably doing something wrong with pressure... when I go to open the filter lid to inspect all this ...junk, I release air vs air release valve...TONS of DE comes smoking out of the returns. Ugh.

And it is pool DE. Bought both in pool store and (laugh if you want) home depot/walmart.
 

TBSNPS

Silver Supporter
Jun 2, 2019
64
Sacramento,Ca.
So, I've been thinking---Pentair recommends backwash at 10 psi above clean ,new DE addition. TFP recommends 10% . for me that is 20 psi /12 psi. The only time the filter has to work hard is when there's algae in my pool, Which has not happened since I switched to TFP in May of this year. Actually I'm wondering why I need a filter at all..lol. My pressure has only risen 1/2 psi since May.
Anyway I am of the belief that using Pentairs recommendation the system over taxes itself causing pressures the system can not deal with, just my thoughts...So once you find the problem please let us know, then keep the balance spot on and backwash at 10%.
Also when I first attempted to repair my manifold , upon start up I would get puffs of DE that lasted anly a minute or two, I figure the DE in the filter then had pressure packed enough DE into the crack to seal it. So my second attempt at repair was successful. Having said all that , You've replaced the manifold. This much drama is like watching the MLB wildcard race...
 

cesmode

Well-known member
Jun 9, 2017
55
Hackettstown
Well thanks for keeping my problem in mind haha. I have multiple pool store guys stumped, pool service guys stumped. No one really wants to come out and figure whats wrong.

So as mentioned yesterday I let the grids soak in a degreaser for oils, dirt etc from around 12pm yesterday to 9am today. Gave them a GOOD hosing (removed some of the pink degreaser, some still stuck on which the bottle said is normal). Saw a little bit of dirt debris etc wash off so thats encouraging. I still have my doubts when I throw some DE in and let it fire up.

As mentioned on Friday I also put the epoxy on the standup pipe (where it meets the black pipe on the bottom to exit the filter, as well as under the lip where the o-ring sits).

This morning I lubed up the pump basket (again).

I also took a look at the check valve which sits BEFORE the pump. I remember on thursday/friday when I had shut the filter off, a TON of DE (smokey water) came blowing out of the return jets. It looked like smoke from a gun if you can imagine that. I was so ******. Up until this point nothing had exited the returns when the filter was off. So I thought the (stock) check valve is failing. Took it out today, its like a teal-ish color, maybe copper staining or corrosion. It feels gummy and looks "chewed" up a very little but around the edges. Enough to make me want to replace it. If I do, it'll probably be later in the week if the wife gives me the go ahead, or next season.

Honestly at this point, if what I did in the last 48-72 hours doesnt fix the problem, Im kicking the can down the road until next spring. I'll replace all of the grids next spring "just because" as well as the spider gasket. Ive invested enough time and money into this problem over the course of the last 2-3 weeks. Ill deal with vacc'ing it up every morning with the bot until we close the pool in early-mid september. I want to enjoy my pool again hah.

I'll let you know in a few hours, once I add DE, how it works out. Water level got low when I was vacc'ing to waste the existing DE. Filling, bot running, and I'll add some DE shortly.
 

cesmode

Well-known member
Jun 9, 2017
55
Hackettstown
Update:
Still believe I have the DE problem. When I fired up the filter after performing the pre mentioned steps, a HUGE cloud of DE came puffing out of the return jets. Water was really cloudy. I let the filter kick on during its normal cycle in the evening, I see DE building up in the usual areas. This is probably because of the issue I still have but also could simply be DE settling from the initial burst.

Will update in a day or two after I have a chance to vac some of it out and see if more comes in.
 

cesmode

Well-known member
Jun 9, 2017
55
Hackettstown
Ok so I think we have some progress.

Got all new grids yesterday. When I drained the filter I didnt backwash (because if it IS the spider gasket causing the issue when I backwash, I didnt want THAT to interfere with determining if the problem is the grids or not). I simply unplugged drain and let it rip. When I did so, pure white cloud came out of all the jets. Pool was horrible. Took 24 hours of setting, vaccing, filling, settling to get most of it out. Water is clear, most of it is gone.

New grids are in. Filter has been running for just over two hours and we dont see as much DE accumulating on the floor. Normally we would see it all across the beveled corners and along the liner seams within an hour. I see some, not a lot. Going to let the filter run until the morning. If all that I see now is all that I see in the morning, I think we are good. That means its just residual DE in the pool thats getting kicked up. I tried to vac the walls (deep end beveled walls are tougher. I know I kicked some DE up there). I might just be vaccing it for a few days until its gone.

And if this is all the case, Im not convinced it was a hole or tear since we inspected those grids multiple times up close, with other well trained pool person eyes. Im thinking the grids were clogged so much that DE was not sticking. I would have thought the degreaser I soaked them in would have taken care of that. Guess not.

Will post an update in a day or so how this finished up.
 
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cesmode

Well-known member
Jun 9, 2017
55
Hackettstown
No go.

And I think I messed up my MPV by attempting to change out the spider gasket. Spent a few hours scraping out the old. Put the new one in place, ridge side up, with pea size silicone adhesive at the ends of the spikes...Letting it sit over night but I have serious doubts.

Im considering switching to a cartridge filter in the spring and rid myself of this DE nonsense.