pressure build up

[splash76]

Hayward sand S200 with 1.5hp pump. my flow seems really good...nice swirling of water in the pump, jets blowing out strongly.
when I turn the pump off....i get a blast of backpressure. or change to backwash setting...it blows water out the backwash with pump turned off to release the buildup.
today I noticed a lot of air is in the sand ...bleed thru the top...it was blowing out air at me strongly....until the water came finally. all the while flow thru the pump going strong and well no interruption.
something is not right....pleas advise.

 

[duraleigh]

Welcome to the forum. :lol:

You have a suction side air leak. Somewhere between the pump and the skimmer(s), air is being sucked into the system. Find that leak and your issues will be solved.

 

[JohnT]

You shouldn't have any swirling water in the pump. That is the problem. It indicates air is getting into the suction side of the pump. The air gets into the filter and is compressed. It could be a leak on the pump basket lid, pump basket drain, low water level in the pool, a sticking weir in the skimmer, a blockage in the suction line somewhere or a leak in the line.