Sand in bottom of pool and whistling sound from filter

[Jess3311]

Luckily, the water in my pool is clearing so although there seems to be a problem, the filter is functioning fairly well.

I’m seeing a lot of sand accumulate on the bottom of our pool now that the water is nearly clear. (Not a little pile here and there, but piles all over the bottom...lots and lots of sand.) I noticed yesterday when cleaning out my baskets (skimmer and pump,) when I turned the pump back on to filter it blew sand, or what appeared to be sand, back into the pool for about 30 seconds and then running clear. I have not been able to see that until this week because the water has been too cloudy until now.
After seeing this, I turned off the pump and placed filter on Rinse for about 30-60 seconds and then back to filter ...again sand blowing into pool for a short time before then running clear.

I have also posted before about a whistling sound coming from the filter (I believe from the multi-port valve.) Now that I’m seeing sand...I’m wondering if maybe the spider gasket or an o-ring somewhere might be the culprit for both. Like I said before, the filter appears to be doing it’s job.

NOTE: We did replace the sand this year and inspected the laterals, which appeared to be in good condition. We filled tank half full with water before putting new sand inside to protect the laterals. This is the only time since installation the multi port valve has been moved off of the filter tank and the filter is only 4 years old I’m hoping the problem is solvable without having to empty the sand again....

Yes, yes...I have been told that we shouldn’t have changed out our sand, but in hindsight we were only doing what we were told to do by our pool supply guy so this is where we are now.

Any ideas? Placed to start checking?

[Teapot]

If the backwash is to fierce, and with your pump it certainly could be! Remember my pump speed controller comment? You can easily push sand out into the plumbing, any issues with the spider gasket and the sand can make its way into the pool. A damaged lateral would be constantly dumping sand into the pool (caveat, usually) so start at the multiport because it's logical, easy and low cost. Consider a speed controller

[Jess3311]

What kind of pump speed controller would you recommend for the type of pump we have?

We are going to check the spider gasket today and I’ll report back...

[Jess3311]

Spider gasket was fine. Cleaned it well and reapplied lube. We did notice that one of the bolts was looser than the others when taking off the top. Everything is running now...we will see...

[Jess3311]

This morning there was no whistling sound after running 6-7 hours continuously. Also I noticed the return flow has not diminished as much as it had been when running that long.

[Teapot]

That's good news, as the dirt load reduced so the less the filter will clog.
How's the sand issue?

[Jess3311]

After checking the gasket and turning everything back on, it seemed like there may have been a few seconds that sand was coming out. It stopped so quickly that I couldn’t get close enough to tell if it was a few air bubbles or sand. Also, I plan to vacuum all the sand up today so I can tell if there is still sand coming in or not. I do think the loose screw may have been atleast part of the issue.

[Denniswiseman]

Be careful as the sand can block your pump
Put a piece of tight material over the skimmer basket to prevent itall going bacl to the pump

[Teapot]

Yes, seconded, skimmer socks are great!

[Teapot]

What kind of pump speed controller would you recommend for the type of pump we have?

Sorry Jess, i missed answering you, Clever-pool pump inverter

[Jenkirb]

Did you determine that the problem was the spider gasket? We are having a whistling sound as well. No noticeable sand in the pool, but definitely not filtering like it should and having to backwash everyday..again we changed our sand this year as well.

[Teapot]

It is quite common for large pumps that are actually too large for the purpose compared to the little filters they are partnered with to be noisy. Sometimes water being let by in the multiport overcomes the spring slightly causing a tone rather than a whistle.
Please post more about your system, pump size, filter size, plumbing etc