The pressure has (previously) run consistently between 15-25 psi. It now reads 7. I have a main & two skimmers. I have tried shutting off the valves, one by one - they each read about 6-7 psi on their own. But when all three are opened, it is still just 7. I know the flow is low, because when I opened this year, I was trying to turn a jammed outlet and I couldn't keep my hand over the jet. Now I can put my hand flat on the jets without much effort. The pump basket is not leaking, nor any of the valves. No visible debris, either, but like I said, it ran fine when I opened - the psi went down after a lot of vac-ing and cleaning out baskets. I was thinking maybe something is stuck, but I don't know how to check or clean it out. The pump basket does not fill completely; there is air on top. I know it used to fill with only a tiny air bubble on top. It also used to really rattle my plumbing when the pump kicked in - pool guy told me my pump was too big for the pool (Hayward super II for 20 x 40 inground). No such rattling now. It's like it just doesn't kick in all the way. THanks for your help. I have been trying to figure out this pool stuff since moving in here. Once, in a former life, I was a lifeguard, and the extent of my pool maintenance knowledge was running the vac on Mondays. Now, I am Mom to 6 pool-crazy kids (well, one is only 4 months old, so he doesn't care YET) who just want me to keep it going and spend my days watching them swim. My husband, who doesn't swim, hasn't taken an interest in pool maintenance so far. SO...your help is very much appreciated!