Sand and debris getting into the pool

Hi all, this is my first post! I’ve had my pool for 10 years and this year my problems started with cloudy water. I noticed that when vacuuming fine silt, it re-appeared in my pool from the return lines. I’ve done a number of things but now I’m getting sand in my pool. Here’s what I’ve done: replaced the sand, inspected the laterals/standpipe, replaced the multi-port head on the sand filter, replaced the sand again (I thought it might be the wrong sand) and re-inspected the laterals again. I’m also getting fine pine needles going right through the filter back into the pool. I’m pulling my hair out right now…don’t know what more I can do! The only other thing I’ve noticed is that where the multiport fits into the stand-pipe, it’s not a snug fit. Is it possible that this is where the problem is? HELP!
 

Texas Splash

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Welcome to TFP! :wave: I doubt the mating area between the MPV and top of the center pipe is an issue. I actually thought you might have a potential chemical issue when you mentioned silt going back to the pool, but then you mentioned the pine needles which would indicate an internal issue in the filter. I almost hate to say this out loud since you've done it 2-3 times already, but I am still suspect of the laterals or connecting hub/knuckle. But let's get another opinion from @Bama Rambler.
 
Welcome to TFP! :wave: I doubt the mating area between the MPV and top of the center pipe is an issue. I actually thought you might have a potential chemical issue when you mentioned silt going back to the pool, but then you mentioned the pine needles which would indicate an internal issue in the filter. I almost hate to say this out loud since you've done it 2-3 times already, but I am still suspect of the laterals or connecting hub/knuckle. But let's get another opinion from @Bama Rambler.
I'm wondering how pine needles would make their way down to the laterals/knuckle?
 

Bama Rambler

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Jun 22, 2009
24,127
SouthWest Alabama
From what you've said that you've done, I'd say that you've covered about everything that could be the issue. But apparently there's something with enough gap to let the stuff through.

When you say there's play between the standpipe and multiport, how much of a gap is there?
It's ususally not an interference fit but there's not much of a gap. Also some filters have an o-ring groove on the standpipe for an o-ring to seal that gap.

You said that you replaced the multiport valve. Did you replace it with a new valve?
 
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There's some play in that gap...I would say about 1/4" movement side to side but there is no groove for an o-ring.

I installed a new valve but only the top half of the valve if you know what I mean. I'm about to replace the bottom half now (the part with the basket) and will let you know if that makes a difference. Thanks
 

Bama Rambler

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Jun 22, 2009
24,127
SouthWest Alabama
Whoa, if there's a 1/4" play in the fit between the stand pipe and the multiport that's your problem. It should be about 1/32" and maybe even less than that. Check the bottom port in the multiport you have and see if there's an o-ring groove in there.
 
Well I replaced the bottom portion of the multipart valve and that appears to have fixed the problem. My suspicion is that when I replaced the sand, there must have been some sort of o-ring on the stand-pipe or inside the valve that got lost when I was removing the sand. Although there is no groove for an o-ring, the previous owner may have rigged up something to fill in that gap between the valve and the stand-pipe. What an adventure this was!