Bubbles in pool intake problem

[jjd11111]

I have a 19,000 round above ground pool. It has a 1.5HP Haywood pump. The basket in the pump has a lot of air in it and a lot of air going into the pool. When I shut it off to backwash I get an explosion of water up out of the skimmer. It filters some but not like it used to.

I see suggestions ranging in scale of O rings, Tightening clamps etc but non-of -these worked so far. I even changed the sand.

What else can I try? Thanks for any help.

 

[mattwm]

When your pump is fully primed and operating for a few hours is there any air in the pump basket?

 

[NUTNDUN]

Are you bleeding the air from the filter as you prime the pump? Sounds like you might have a sand filter with a multiport valve?