DE coming into the pool only after pump has been off for a while

[mcbeth]

My husband and I bought a house over the winter, that came with a great inground pool. Only problem was that neither of us knew anything about pools. Over the past month or so I've learned a lot and we finally got our pool into swimming shape, or so I thought. The water is clear, the chemical levels are good, when we keep the pump/filter running continuously, everything is great! But, now that the pool is clean I want to only run the pump say 12 hrs/day. When we turn the pump off, there are no problems, but when we turn it back on again, a whole bunch of DE enters the pool.

At first I assumed this was a filter problem. I examined the grids in the Hayward filter. There were no holes but some of the grid plastic that connects to the assembly were broken (the top of the grids has a split plastic end, for lack of a better term and some of those were broken), so I figured that must be the problem. So I bought a whole new filter grid assembly, thinking that surely we would have no problems after doing that. Well, after we got it all up and running, last night we turned off the pump and when it turned back on this morning....DE all over the pool, again.

So clearly something else is wrong here. Any idea what this could be, has anyone experienced this before?

More details about my pool if you need it: in ground, Mineral Springs saltwater pool, brand new Hayward super pump, Hayward DE filter with new grid assembly (requiring 6 lbs of DE)

 

[OldPoolMan]

Hi McBeth. As long as you run the pool 24/7 you will not see DE in the pool because all of it will eventually will lodge in the filter grids even if the grids have a tear or hole in them, and or the manifold is cracked or broken. What happens when the pump turns off is that some of the DE falls off the grids. So when the pump I'd restarted some of that material will go thru any openings and return to the pool. The offshoot is that you need to disassemble the filter again and inspect every part in it. The DE is going thru the filter somewhere. Good luck to you.

 

[mcbeth]

But it's a brand new filter assembly (all new grids, new top assembly piece, new bottom assembly piece) and it came assembled (so I didn't mess that part up), so how can the DE be going through the filter?

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Additionally, when we first put DE in the pool (via the skimmer), no DE returns to the pool at all. If there was a hole, wouldn't DE come back into the pool at that time? Why is it that it only enters the pool after the pump/filter has been off for a long period of time?

And thank you for taking the time to read and reply.

 

[JoyfulNoise]

How long does the plume of DE last for when you first turn on the pump?

When you charged up the new grids, how much DE did you use and how long did you let the pump run for?


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[mcbeth]

I didn't actually see it when it turned on, but there was enough DE in the pool to visibly line all the crevices in the deep end and collect on the stairs. When I first charged up the grids, we added 6 lbs of DE (recommended amount for the pool/filter). I can't recall exactly how long the pump had been running when I shut it off - I'd say 8 hours at least. Then it was off for 12 hours, before it turned on again.

Today we backwashed the filter and only added 4.5 lbs of DE in hopes that maybe there was just too much DE? (doubtful, but I'm hoping)

 

[JoyfulNoise]

Can you please check at some point if it is a continuos stream of DE or only a burst? If it is just a burst, time how long it lasts. You may need help from someone to turn the system on/off while you stand at the returns.

I'm only asking because it's important to know. A continuos stream means a tear in the grid fabric, improperly mounted retaining assemblies or broken pipes. A short burst that clears up right away can actually be quite normal.

When I tear down my DE filter each season, the initial startup typically causes a lot of DE fine particulates to initially make it through the quad cartridges. My pool goes cloudy for a couple of hours and then clears right up. The recharging procedure is a little finicky and I have a procedure that I use that seems (at least to me) to minimize the amount of DE blow-through.

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Oh, and do you have a plunger style backwash valve or a multiport? When was the last time you opened it up to inspect the ring seals?

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Oh, and I love Carmel, NY!! I grew up on Long Island and lived in NYC for about 10 years. I worked up in northern Westchester County and was a frequent commuter on the Saw Mill and Taconic Parkways!! My wife and I loved driving up in your part of the woods every fall to catch the beautiful Hudson Valley colors...just about the only thing I miss about NY.

 

[vinper]

Cool ,I grew up in Brewster, went to B.O.C.E.S in high school think that was in Carmel . Lived off route 22

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could be back feeding after pump shut off

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look at pump after shutting it off ,does it look like water draining back. when you turn it on does it take a while to fill filter before coming out jets or does it come out immeidietly?

 

[JoyfulNoise]

Tisk, tisk, tisk...I noticed both of you DID NOT read the Before You Post sticky in Pool School....can you update your signatures with pool equipment specs. It helps out enormously when troubleshooting.

 

[s281er238]

So what happend at the end Im
Having the same issue de getting back even with her filter kit complete replacement of quad De 80 and & pound of de let it sit for 2 min turn it on and And you have. 45 set of de coming in and it’s clear untie next but was never like that for past 8 month which it was first installed all bend new pool. I replaced everything. I noticed D.E. getting into the pump and basket after I turn it off why I don’t know. Maybe I have 2 bad filters lite and manifolds I don’t know it’s a mystery