First I'd like to say I've learned a ton from this site so thank you. Now to my problem. I opened my pool today and initially everything was fine. Before opening my pool this year I changed from hoses to pvc pipe for plumbing and all was good with no leaks. When I opened everything to let the water into pump, filter and lines everything was good. I turned the pump on and because I didn't rinse the sand filter first I got a lot of sand spit into the pool. Didn't think it was a big deal and I just vacuumed it up with the rest of the pool. When I vacuumed the pool I vacuumed it in the filter position because the water is clear and I only have a well to fill my pool. When I got towards the end of vacuuming I found more sand in the pool but noticed my pressure at pump and filter was low so I thought I should backwash before continuing. When I back washed nothing came out. Same with rinse and filter settings. When I put pump on recirculation or waste it is fine. But again, no to little flow on filter, backwash and rinse settings. Both skimmer and pump basket are full with no air bubbles in pump basket. I have a Hayward pump, vari-flow valve and sand filter on an above ground pool. I am thinking something in the filter is clogged but wanted opinions first. Thanks for any help in advance. And sorry for the lack of a signature. I will get that done before my next post.