Changing sand

[BluePool203]

I replaced the sand in my Hayward S-210T Sand Filter with Mystic White II pool filter sand. When I backwadhed the filter some sand came out. Is that normal?

 

[Texas Splash]

I replaced the sand in my Hayward S-210T Sand Filter with Mystic White II pool filter sand. When I backwadhed the filter some sand came out. Is that normal?

Normally you don't expect to see sand come out of the return jets. Assuming this was your standard #20 silica pool sand, some things to watch out for might include:
- Did you run it on RINSE long enough after the backwash? Maybe a good 20-30 sec or so once the sight glass is clear?
- Did you put some water in the filter before dumping the new sand in? Helps to prevent separation or breaking a lateral.
- Did you cover the top of the center standpipe before adding the sand as to not get any inside of it?

If you continue to get sand out of a return, you may need to go back into that filter and inspect the laterals.

 

[BluePool203]

It wasn't from the returns it was from the backwash on the filter. I backwashed it for 2 minutes and then I rinse it until the site glass is clear. I filled the filter half way with water and plugged the end. The first time I backwashed the filter there was a lot of sand and the next time I see a little sand. Each time I do it I keep seeing a little sand.However I'm worried the sand will go through the pipes to the returns if I switch it to filter. Is it normal to see sand come out after just changing it?

 

[Texas Splash]

It wasn't from the returns it was from the backwash on the filter.

if sand is not escaping out of the return jets, it sounds like you are seeing some sand escape from the WASTE pipe during backwash? Is that correct? If I'm understanding the situation correctly, nothing should be escaping to WASTE while you are in backwash mode. If I misunderstood, please let me know.

Also, did this problem happen immediately at spring opening, or only after you changed the sand?

Last, can you post a pic of your filter?

 

[BluePool203]

It's from the waste pipe. Before opening the pool I changed the sand, hooked up the pump and backwashed the filter. Pictures of the filter and sand below.

You can see the sand off to the right of the pump. Cutting the grass blew some of it away. Just to the right of the pump is the first backwash. Where the waste hose is the 2nd backwash, a lot less sand came out. The thrid time was even less. Should I keep backwashing and rinsing until no sand is coming out?

Thanks for replying.

 

[Texas Splash]

I do see the sand now and have a better understanding of what's happening. Essentially sand is seeping out of the waste line (not return jets) during backwash. Since this started after replacing the sand at opening this year, I think of the following possibilities:
- Filter was filled with too much sand. If that's the case, it should eventually blow-out the excess and stop.
- Pump is pushing too much water for the filter (doubtful if same pump as last year)
- Something odd about that batch of sand?
- Multiport Valve (MPV) problem; maybe a stretch, but after winter maybe it got freeze damage

I'm going to ask @Bama Rambler to review the past couple posts to make sure we're not missing something.

 

[Bama Rambler]

When you replaced the sand what type did you use?
How much did you put in?
Do you remember how far the level was from the top of the filter?

My suspicion is that it'll quit ejecting the sand in the next few backwashes and everything will be fine.

If you look at how a sand filter backwashes, it agitates the sand and in a new fill, some of the sand will rise up in the stream and flow out the backwash port.

 

[BluePool203]

Mystic White II is the filter sand I used. I put 4 bags for a total of 200 lbs and two scopes of old sand to make up for what didn't make it in. I'd guess the sand was 8 or so inches from the top.