DE entering pool thru skimmer and drain when the pumps off.

Aug 7, 2011
20
So Cal
The filter and pump is higher up than the pool. I also have a spa connected to the system. DE starts to enter thru the skimmer and drain when the pump shuts off. There are no signs of water leaks from the pump and the filter. Last week I did a pressure check on all the pipes when the pool was empty. This is my first time starting the pool's equipment since I just moved in 2 weeks ago. The pump is a brand new variable speed pentair. There used to be a check valve which i took out in the suction line just before the pump. In lieu of the check valve, I raised/extended the 3 way valve (skimmer/drain) for the suction higher up than the pump basket in hopes that I can eliminate the need for a check valve. Could it be possible that I have an air leak from the filter but no signs of water leak? Should I just install a new check valve and call it a day?
 
Re: DE entering pool thru skimmer and drain when the pumps o

Put the check valve back in and lower the valve unless raising it cleaned up the plumbing? I have a check valve after the pump and before the filter which I believe is more common but either location should be fine.
 
Re: DE entering pool thru skimmer and drain when the pumps o

It sounds like you have a leak somewhere allowing the plumbing to drain a little when the system is off. Tell us more about your equipment. Does your filter have a slide valve or a multiport? Etc.

Is there any water coming out of the waste port when the pump is running? If so, then that may be your problem.

Adding the check valve back will stop the DE from going back to the pool but it really won't solve the problem if there is one.
 
Re: DE entering pool thru skimmer and drain when the pumps o

Bama Rambler said:
It sounds like you have a leak somewhere allowing the plumbing to drain a little when the system is off. Tell us more about your equipment. Does your filter have a slide valve or a multiport? Etc.

Is there any water coming out of the waste port when the pump is running? If so, then that may be your problem.

Adding the check valve back will stop the DE from going back to the pool but it really won't solve the problem if there is one.

I have (2) 2" suction pipes to equipment pad and I have (2) 2" return pipes from pad to pool.

The 2 drains (spa&pool) and the skimmer pipes are all 2"
The return jets are all 1"
I have a hayward DE-4800 filter with no backwash valves or anything fancy, and a brand new pentair variable speed 3hp pump.
I don't have a check valve.
The pump/filter sits 22inches above the pool water line. The spa sits 7inches above the pool water line.
I have 4 return jets to the pool (3 in the pool, 1 in the spa) If i switch the valve to the spa, i have 4 return jets to the spa. Combined I have 8 retur
 
Re: DE entering pool thru skimmer and drain when the pumps o

Are you losing prime at the pump? I didnt see you mention that. If you are not then i dont think that an air leak is the problem as you arent having water flow. Does the de return back to the spa if the suction is set for it?

Could you have too much DE in the filter? I overfilled mine when I first set it up Nd I would get a cloud of de in the check valve. I'd see this within a minute but my check valve is between my pump and filter.
 
Re: DE entering pool thru skimmer and drain when the pumps o

PoolGuyNJ said:
A check valve between the pump and filter is the correct fix.

Scott
My pool supply told me to put the check valve before the pump on the suction line.
Just to clarify, are you advising me to put the check valve between the pump and filter? That would be the line that forces water away from the pump and into the filter right? I just want to double check because that would make more sense to put it where you mentioned. Can anyone confirm?
 
Re: DE entering pool thru skimmer and drain when the pumps o

Listen to Scott. He has a lot of experience in this area (as well as many others). If he says it should go on the discharge of the pump then it should.
 
Re: DE entering pool thru skimmer and drain when the pumps o

carlscan26 said:
Are you losing prime at the pump? I didnt see you mention that. If you are not then i dont think that an air leak is the problem as you arent having water flow. Does the de return back to the spa if the suction is set for it?

Could you have too much DE in the filter? I overfilled mine when I first set it up Nd I would get a cloud of de in the check valve. I'd see this within a minute but my check valve is between my pump and filter.

What is "losing prime at the pump" mean?? Sorry, im fairly new. If it's what i think it means, the clear plastic lid for the pump basket is always full of water to the top. Its a brand new pump.
I think the DE only returns to the pool drian/skimmer. I never checked the spa actually. I should mention that the spa is 7 inches higher than the pool's water line.
I only put 6 coffee cans of DE which is what my pool supply told me, even though the DE box says to put 12 cans... So if anything I put less.
 
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Re: DE entering pool thru skimmer and drain when the pumps o

Lets stick you your situation for now.

When your system is off, you stated that DE is flowing back into the pump and down to the drains. This DE is coming from the filter. The only way it can leave the filter this way is if air is getting in it. This can happen from a number of places but is generally found in a location that is higher than the filter intake's elevation.

This doesn't mean you are losing water when the system is running. Often, the running pressure seals things up.

By inserting the check valve between the pump and the filter, if air leaks get into the filter, water can only go out the return side. That puts the grids between the DE and the pool. No DE is lost. Without the check, water can flow in the opposite direction when the system is off. Its the exact reverse of charging a filter but not a backwash, which has a different flow path.

Scott
 

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Re: DE entering pool thru skimmer and drain when the pumps o

A check valve is the solution to keep water from flowing backwards and to keep the DE from exiting his filter from the water intake side.

The question is why is water flowing backwards?

The OP has an elevated equipment pad. An elevated pump and filter, etc. maintain prime because they are in a closed system that is in equilibrium created by a vacuum effect (I may have this part wrong, Mark to correct me, but the point is that it's in a balance maintained by being a closed system). If there is an air leak in the plumbing then the equilibrium is lost and water will drop. Try opening the air relief valve on the filter when the pump is off and see what happens. In my case, since I have a check valve between my pump and filter, water leaves the filter but my pump still stays full.

I've PM'd Mark to weigh in here with his expert opinion, but here's my arm chair thoughts: There's water under high pressure in the equipment pad (for obvious reasons) . When the pump shuts off, the water is no longer under active pressure and is going to return to it's equilibrium state (Mark please insert technical terms and explanation here) which will involve some water movemeent. In the OPs case since there is no check valve the path of least resistance for water between the pump and filter is back towards the pool, which will draw back some of the water in the filter pulling some DE with it. Also, no check valvewill allow the diffusion to kick in and the DE is moving out of the high concentration area (the filter) to the area of low concentration (the pool)?

That's all I have :cheers:
 
Re: DE entering pool thru skimmer and drain when the pumps o

Carlscan, thank you for your insight! I bought and installed new rubber o-ring for the filter lid half, I took apart the air bleeder and the pressure gauge, I made sure all the o rings were in and put new teflon. So I can assure you there are no leaks from the air bleeder area and the filter lid half. I also installed new input/output (the black color collars and pipe, hayward items) that go on the lower portion of the filter. So the only thing I didn't change was the lower drain plug for the filter but I highly doubt air is entering from there. Did I miss anything? My pump is brand new intelliflo that never needs to prime! I'm going crazy over this. I bought a check valve but I'm holding off on installing that because I rather fix the issue versus put a bandaid, unless I have no choice sits the pump sits higher. The original piping (copper) had a check valve.
When the pump is off, I opened up the air bleeder and it emptied the de/water into pump basket and out into the pool at a much faster rate.
 
Re: DE entering pool thru skimmer and drain when the pumps o

I should restate. I forgot good old gravity will do it too, especially with a very clean system. What brand of DE are you using?

Scott

PS Just put the check valve in and this will stop.
 
Re: DE entering pool thru skimmer and drain when the pumps o

[quote="mas985The only other way I can see DE migrating from the filter to the skimmer is if you have solar with a vacuum release valve. Without a check valve, water would flow backwards through the filter out of the skimmer when the pump is shut off.


[EDIT] Just thought of something else. If the valves were set for spillover and the pump is shut off, water will flow from the spa out through the skimmers until the spa reaches the pool level.[/quote]

So that breaks the closed system right?

liftmys10 - Mark asked more clearly what I tried to ask earlier - does it still happen if you have the valves setup for spa mode vs. pool mode, vs. spillover mode, etc?
 
Re: DE entering pool thru skimmer and drain when the pumps o

PoolGuyNJ said:
I should restate. I forgot good old gravity will do it too, especially with a very clean system. What brand of DE are you using?

Scott

PS Just put the check valve in and this will stop.
DicaLite DE
Yeah Im getting closer to just putting the check valve.
On a seperate note, at my other house when the pump shuts off, I can actually hear air being sucked thru the air bleeder and no DE goes back in the pool!!!! It's a pentair 4800 filter with a multiway valve. I wonder if the multivalve has a check valve built in?? The pool/filter is about the same level as the pool water.

Im going crazy! :hammer:
 
Re: DE entering pool thru skimmer and drain when the pumps o

mas985 said:
When the pump is off, listen close to the filter for bubbles rising.

I tried that and when i put my ear on the filter, i can hear 1 or 2 tiny bubbles going up every 2-3 seconds. But how on earth can I still have air leaking in? This is not my frist pool and I always have maintained my pool at my other house. Granted I just got this place (the one with DE leaking out) and it's my frist time testing out the whole system so I havent fixed all the bugs yet. But I did do a pressure check on all the lines before filling up the pool. All the pipes held 21psi for 10 minutes.
 
Re: DE entering pool thru skimmer and drain when the pumps o

The only other way I can see DE migrating from the filter to the skimmer is if you have solar with a vacuum release valve. Without a check valve, water would flow backwards through the filter out of the skimmer when the pump is shut off.

[EDIT] Just thought of something else. If the valves were set for spillover and the pump is shut off, water will flow from the spa out through the skimmers until the spa reaches the pool level.

What about these two things?
 
Re: DE entering pool thru skimmer and drain when the pumps o

mas985 said:
The only other way I can see DE migrating from the filter to the skimmer is if you have solar with a vacuum release valve. Without a check valve, water would flow backwards through the filter out of the skimmer when the pump is shut off.

[EDIT] Just thought of something else. If the valves were set for spillover and the pump is shut off, water will flow from the spa out through the skimmers until the spa reaches the pool level.

What about these two things?
Haven't been home yet but will post results asap. Thanks!
 
Re: DE entering pool thru skimmer and drain when the pumps o

When I set the suction to "drain mode" it sucks from the pool drain and the spa drain at the sametime. When I set to skimmer mode, it sucks from the pool skimmer. When I set the return to the pool, 3 jets are in the pool and 1 jet is in the spa at the sametime.... When I set the return to spa, 4 jets are only for the spa. So what is spillover mode? The spa is constantly spilling over when the skimmer is on and either pool or spa jets are on. I don't know if this is right but I can actually drain my spa completely out if I put 100% suction on to drain and 100% return to pool!
 

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