Help! Not sure why there's sand in my return.

[leslieinbham]

Hi. I have an 18 ft round AG pool with a 19 inch waterways sand filter and a Hayward pump.
When I started working on the pool this spring, I noticed the TON of sand that had accumulated in it. Since I have little guys, I assumed that it came from the unfortunately nearby sandbox, so I went about removing it. I was wrong, of course. Two of the laterals on my filter had come unscrewed somehow so the more I tried to get the sand out, the more got pumped into the pool. And at some point, this blew out my original pump. While I was waiting for the replacement pump to arrive, I replaced the sand in the filter, checked the laterals for damage, cleared all the offending sand out of the places in the filter where it didn't belong and (now that I understand my errors and oversights) I reassembled the filter far more carefully than I had assembled it in the first place. The pump arrived and I figured that once I had the chemistry back under control, we were in the clear. Well, today I was vacuuming the pool and I could *hear* sand re-entering the pool through the return valve. I'm trying to figure out why this is happening because I really gave all the filter parts a thorough inspection and there were no cracks or holes in the laterals, all of them were properly tightened, etc. Is it possible that this sand (filter sand) is excess from the sand filter? I put in about 120 lbs of filter sand when I took out the old sand and replaced it. I've seen recommendations for both 100 lbs and 150 lbs for a 19 inch sand filter, so I was thought I was being as safe as I could about it.

The sand discharges most heavily in the "rinse" phase of the backwash process, but it shows in the sight glass throughout the backwashing process. I'm slamming the pool now, so I'm backwashing a lot. Is backwashing going to take care of the excess sand over the course of the treatment? My kids will be out of school really soon and I don't have an opportunity to take the filter apart and put it back together again without lots and lots of "help." Any ideas? Thanks so much! --Leslie

 

[woodyp]

May be time to inspect the gasket underneath/inside the multiport valve on top. Easiest thing to do first. Welcome to the forum.

 

[leslieinbham]

Thanks. Am I looking for more (grrr) sand? a water leak? I love, love, love this pool but it is wearing me out right now--sorry. I replaced the multiport valve port this winter b/c I had the floppy handle thing going on and it wouldn't shift out of the backwash position. There seems to be less sand coming in the return after I've gone through backwash and rinse, if that matters at all. --Leslie

 

[DanielP]

Aside from sand already in the return lines from last year, the possibilities are the gasket, the multi-port valve, or the plumbing in the tank. If a lot of sand is coming out during the backwash you have too much sand or too big of a pump, but that won't put sand in the pool. Not backwashing and rinsing the sand before turning it to filter for the first time adds sand to the pool.


P.S. I fixed my floppy handle by buying a nylon washer that was missing from under the handle as well as the handle itself. It took forever to figure out that problem because I thought the pool store kept selling me a gasket that was too thick. Local pool store wanted to charge me $29 for the handle alone when I called for a price, but I found those two parts and a couple gaskets that seals the vertical shaft on to diverter plate to the top cover for $25 shipped.