Sand Filter woes

[twosocks90]

I have a two years old Hayward S210T filter on a 28ft AGP with a recurring problem of dirt bypassing the filter when we vacuum.

I replaced the spider gasket assembly which didn't help. Then I deep cleaned the sand which didn't help. Finally I removed the lateral assembly and found a crack in the bottom of it between the laterals. A new assembly has been ordered and should be here the day after tomorrow.

Here's the thing. When i took the lateral assembly out I noticed deep scratches / gouges on the top of the standpipe and the bottom of the filter head assembly where the standpipe goes in. Could dirt be leaking through there? Is there supposed to be a seal of some sort between the standpipe and filter head?

This thing has been driving me nuts for weeks. We haven't been able to swim yet this year and I keep throwing money at it! I need to get this fixed!

 

[Texas Splash]

Is there supposed to be a seal of some sort between the standpipe and filter head?

I believe the O-ring under the multiport valve sealing it to the top of the filter housing is all. I'm not aware of anything at the top of the standpipe itself or in the bottom of the MPV where it mates. It usually sits snug in the bottom of the MPV which is probably why it's scratched. In fact, some owners get into a tough spot later when that standpipe won't let go of the MPV. But in FILTER mode, the water is flowing down through the sand then up into the laterals and finally the standpipe, so I don't think sand could get pulled up at the top where the two meet unless the filter was too full of sand.

But I have to ask this one ... are you sure the stuff blowing-out is sand? Have you captured it? Is it gritty like sand, or could it be soft/fluffy like algae?

 

[twosocks90]

I don't believe the stuff blowing out is necessarily sand. I believe it's dirt that was picked up by the pool vacuum. Whether or not it's algae I can't say, but the pool chemistry is good and the water is clear, except for when the bottom gets stirred up by vacuuming attempts or the return starts pumping dirt back into the pool.

I used silicon and a piece of plastic to try to repair the crack until the new lateral assembly gets here. I suppose it's possible that my repair failed instantly which is causing the problem again. I just don't want to have to install the new lateral assembly only to find there's yet something else I need to fix.

 

[Texas Splash]

Do you remember the brand name of the sand you used? It wasn't Quikrete was it? There were a couple brands out there have been know to be a bit small in size and would pass through the laterals. Hopefully yours clearly listed #20 pool silica sand on the packaging.

 

[twosocks90]

Bought it from Menard's two years ago. I don't remember the brand other than it was labelled as pool sand.

 

[twosocks90]

Update, I replaced the lateral assembly and the sand. So far we've vacuumed once and had no dirt blow back into the pool.

So, good news!