Sand "leaking" from filter, then stopped?


Jul 6, 2018
Syracuse, NY
Hi all,

24,000ish gallon ingound. Hayward pu,p and Hayward s220T sand filter. Mesh safety cover (the kind with the springs attaching it to hidden anchors).

I opened it for the summer a few weeks ago, for the first time (moved into the house mid-summer last year and had to replace the liner so it was not a "normal" summer for the pool).

The pool water was pretty dirty when I opened and there was some algae, I brushed and vacuumed and shocked until it was clear and stable, about 2 days of work. After this, I realized there was still a LOT of sand on the bottom (I got in the pool and verified it was sand by touch, I know it wasn't mustard algae or anything else). I vacuumed thoroughly. The next day, the sand was back. Vacuumed again, figured maybe it was still settling out of the water, or I'd stirred it up when I vacuumed. This repeated for almost a week - sand would magically be back the next day, in significant amounts. Seemed evenly spread around the bottom, although there was always a lot near the filter returns.

I did some googling and decided based on what I saw that there must be a broken lateral in the sand filter. So I ordered a new lateral assembly, which took a few days to arrive, and then I was too busy for a few days, so about a week went by. I was still vacuuming every few days at this point.

Well, during that week, it became clear that the sand was gradually decreasing in volume each day. By the time I got a half a day to really work on the pool, I realized that the sand was pretty much completely gone, so I vacuumed one last time, and there really hasn't been any sand at all since then (about 4 days ago).

This is a long winded story, basically I'm just confused. Where could this sand have been coming from? If there really was a broken lateral, why would it have magically stopped? If it wasn't from the filter leaking, where could it actually have come from?

I suppose at this point the problem is gone, I will probably return the lateral assembly. But I'm just super curious about why this happened, and I'm wondering if there could still be some issue lurking...

Texas Splash

Mod Squad
TFP Expert
LifeTime Supporter
A broken lateral shouldn't just stop allowing excess sand to pass. Since you confirmed it was sand, I wonder if the filter was overfilled with sand in the past by the previous owners? That or you lost so much sand it's now empty? I suspect the pressure gauge should be really low if that was the case though. Any pattern of when the sand was spewing-out (i.e. only when pump was on high)? The only other thing I can think of is the unknown condition of everything inside that filter from previous owners.


TFP Expert
LifeTime Supporter
Jan 6, 2010
San Dimas, CA (LA County)
Perhaps you didn't rinse long enough after backwashing and a bunch of sand was in the pipes. Then a little bit comes out every day. The sand you saw every morning was not the same sand you vacuumed. Once it all got blown into the pool, there was no more to vacuum.