Filter media blown into pool on pump start/stop only

[budgetplan1]

Obviously, something is awry. Changed filter media about 3 weeks ago, apparently something was dislodged. If I were to leave the pump on 24/7 it wouldn't be a problem as no media (Zeolite) blows back into pool except for when pump is stopped, then started. I held a strainer over a return when starting pump and media comes out for about 30seconds when pump is started, then diminishes to nothing during normal operation. Not a lot, but enough to know something is not right.

*Sigh*...really not look forward to emptying filter again to check laterals. Possibly multiport valve/spider gasket issue? That's easier to deal with. Or I'm wondering if there may be a 'pocket' around a lateral 'hinge' that allows it to move a bit when filter drains down/is restarted, allowing an small opening for media to pass into standpipe momentarily. Media also visible in sight glass during backwashing.

Unfortunately I really can't think of any way for media to get into standpipe aside from the lateral area.

 

[Isaac-1]

It may help if you tell us the brand and model of your filter

Ike

 

[Bama Rambler]

I'd check the multiport first. Since it quits bypassing media once it starts running I'd suspect the multiport first.

 

[budgetplan1]

Hayward S244T sand filter; 300lbs sand, 150 Zeoilte. Sp714T Multiport.

Just took the top off the Multiport, no obvious issues. Looks like spider gasket in this model molded into valve top. Good shape, no cuts/gaps. Re-lubed and re-assembled. Guess I'll pull the multiport off the filter tank.

Since it only blows back on startup and more severely when pump/filter has drained down (like when opening/pump, cleaning basket/backwashing) me thinks something is 'moving' around somewhere and then resumes normal 'place' when filtering resumes. Media blown back into pool is definitely to large to be pulled through intact lateral openings. Oh well, I have a few extra laterals sitting around.

9am and mosquitoes out already; looks to be a fun day!

 

[Smykowski]

Try inspecting the laterals themselves. If the laterals aren't fully seated in the down position, a small gap on the bottom will allow sand/dirt back into the pool. Ask me how I know this.....

 

[budgetplan1]

Try inspecting the laterals themselves. If the laterals aren't fully seated in the down position, a small gap on the bottom will allow sand/dirt back into the pool. Ask me how I know this.....

Can you say "I'll take New Lateral Assembly for $55, Alex?"

Looks like the ball/socket joint for some of the laterals is pretty worn/eroded. When I Went to fold up laterals to remove from tank, one of 'em fell right out. Seemed pretty tight 3 weeks ago, though. Anyway, looks like I may as well go for replacing the entire thing...guessing I'll be on re-circulate for a few days. Rather just go new as opposed to re-assembling this and hoping for best; pointy nubs on lateral balls worn off on most...probably allowed laters to shift upon adding new media, open a crack for media to push through. Emptying the filter tank of media is just too much work. Can get new assembly for about $55 so may as well just do it. 18 years on this one. Probably a 'seat laterals fully down' issue as well. Unless perfectly alligned looks like openings between lateral ball/socket are imminent.

This particular lateral will not lock/stop in normal down position. It moves further freely, allowing a gap to open. I'm guessing that's the issue.