Replace fitting from pool sand filter to the multiport selector switch thing

[ArmatageShanks]

I got the older sand filter, and mine pump out sand during backwash. Any ideas there?

Its meant to, backwash is for washing the sand

 

[upup]

It go out on grass, and their is sand, about a cup full. Maybe I must seal the hole where the small pipe goes into. No sand in the pool, just on backwash on the grass.