Filter Sand accumulating in Pool

vantiem5

Gold Supporter
Jun 29, 2021
35
South East Michigan
Pool Size
33000
Surface
Vinyl
Chlorine
Liquid Chlorine
Every week I am getting an accumulation of filter sand in the bottom of the pool directly below the return lines. Mostly below the return line in the deep end and a much smaller amount below the return in the shallow end. I would estimate that I vacuum up about two cups a week. It is definitely filter sand and not dirt or sand blowing into the pool from the yard. This has never happened before. The only thing that I can say that is new this year is that there is a very small pin hole leak in the sand filter just below the multivalve. We are talking drops of water slowly leaking and not a stream. I estimate that the sand in the filter was replaced about ten years ago and nothing has been added or subtracted in that time. I back wash at least once a week.

Has anyone experienced this problem and/or have any ideas about why this is happening.
 
Sand is usually an indication that one of your laterals or perhaps the center pipe/hub assembly i showing signs of damage. You mentioned the sand was replaced about 10 years ago, but do you know how old the filter itself is? That tiny pinhole, it's actually in the filter body itself?
 
Sand is usually an indication that one of your laterals or perhaps the center pipe/hub assembly i showing signs of damage. You mentioned the sand was replaced about 10 years ago, but do you know how old the filter itself is? That tiny pinhole, it's actually in the filter body itself?

The filter body is original to the pool install in 2001 so it's 20 years old this summer. The pinhole is in the filter body itself.
 
The pinhole is in the filter body itself.
Well, unfortunately it may be time to consider a replacement. The sand may be an internal issue and repairable, but the pinhole is a subtle sign of vessel integrity compromise. It cannot be repaired, and those things can go quickly. Quite dangerous actually. I'm more concerned with that pinhole than I am the sand to be honest.
 
Well, unfortunately it may be time to consider a replacement. The sand may be an internal issue and repairable, but the pinhole is a subtle sign of vessel integrity compromise. It cannot be repaired, and those things can go quickly. Quite dangerous actually. I'm more concerned with that pinhole than I am the sand to be honest.
Ugh. I was afraid of that and kind of figured that a replacement for the filter would be needed. The plan at this point is to limp along until the end of the season which isn't that far from now and to begin the search for a replacement filter. Thanks for your input today.
 
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Well, unfortunately it may be time to consider a replacement. The sand may be an internal issue and repairable, but the pinhole is a subtle sign of vessel integrity compromise. It cannot be repaired, and those things can go quickly. Quite dangerous actually. I'm more concerned with that pinhole than I am the sand to be honest.
Hey Texas, just asking for curiosity's sake--could that pinhole compromise the filter to a degree that it explodes?
 
Hey Texas, just asking for curiosity's sake--could that pinhole compromise the filter to a degree that it explodes?
I suppose it could which is why I said that earlier. As an example, think of a rust spot on the outside of an AGP. You see s small rust area on teh exterior until you get behind it and are surprised by how extensive it is. Of course this is more of a composite/fiberglass product, but I wonder what it's like on the backside. You might take a look at some point.
 
I sure hope OP reads your reply and doesn't try to wait it out. I get worried about that kind of stuff. Filters can be scary.
 
Every week I am getting an accumulation of filter sand in the bottom of the pool directly below the return lines. Mostly below the return line in the deep end and a much smaller amount below the return in the shallow end. I would estimate that I vacuum up about two cups a week. It is definitely filter sand and not dirt or sand blowing into the pool from the yard. This has never happened before. The only thing that I can say that is new this year is that there is a very small pin hole leak in the sand filter just below the multivalve. We are talking drops of water slowly leaking and not a stream. I estimate that the sand in the filter was replaced about ten years ago and nothing has been added or subtracted in that time. I back wash at least once a week.

Has anyone experienced this problem and/or have any ideas about why this is happening.
Is that leak coming from the port/bulkhead where the multiport plugs into the filter? or lower on the filter body itsself? The bulkhead could be leaking. You can change that oring out.

The sand is coming from a missing or broke air relief screen or the tube that is connected to. Open the lid. The screen is on top above the sand check it. If it looks fine follow that tube down into the sand about 6inches. Make sure it has not split. Its almost aways that.

Next would be the diffuser pipe has blown off, thats the pvc pipe on top that goes into the wall.

Next would be the lateral pipe under the top pvc pipe going into the wall. Less likely but seen it happen. Last would be one of the laterals at the very bottom.

Let us know what you find.
 
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Is that leak coming from the port/bulkhead where the multiport plugs into the filter? or lower on the filter body itsself? The bulkhead could be leaking. You can change that oring out.

The sand is coming from a missing or broke air relief screen or the tube that is connected to. Open the lid. The screen is on top above the sand check it. If it looks fine follow that tube down into the sand about 6inches. Make sure it has not split. Its almost aways that.

Next would be the diffuser pipe has blown off, thats the pvc pipe on top that goes into the wall.

Next would be the lateral pipe under the top pvc pipe going into the wall. Less likely but seen it happen. Last would be one of the laterals at the very bottom.

Thanks ferretbone for your reply...

The leak is is in the filter body itself. I will check for a broken air relief screen. I assume it is broken because the sand issue is new this year after several years of no problems.
 

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