I have a pentair pool pump and it spitting sand back into the pool does anyone know how to fix this?

Question

it is a sand filter we just purchased it last year ty

Answer 1

It's one of two things:

1/ The multiport's key stem gasket is history or the actual multiport's interior has deformed due to an over heat situation from either the pump running dry for an extended period or someone shutting off the pump while a pool heater was running. A visual inspection of the multiport interior will let you know.

OR

2/ The lateral assembly in the bottom of the filter tank has a crack in it. The laterals have small slits, that allow water, but not sand to get through. If there's a crack in them, it will be large enough for sand to pass and it'll shoot back to the pool. The remedy here is to drain the tank of water and remove the sand, replace the damaged lateral finger ( or the whole assembly), refill with sand and away you go.

Of course, it's also possible that you accidentally vac'd up sand with the filter set to backwash and then switched over to filter. That can explain it as well, since that would put the debris on the wrong side of the sand bed and I HAVE seen someone do this.