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.