Over the last few weeks I have noticed that the water level in my skimmer has been getting lower and lower. Today I started investigating. I started by trying to raise the level in the skimmer with the gate valve, but I have turned the gate valve so it is as closed as possible and my water level is still just barely touching the bottom of the collection tube. It dawned on me then, that maybe there isn't enough flow going through the system. My system is set up so that my overflow splits, half goes into the skimmer and half dumps into the sump. It is very apparent now that I have VERY LITTLE flow going through my overflow. So I pulled out my return pump and cleaned it, thinking it wasn't pushing enough water up and out of the sump...it appears to be working fine. But somewhere in this system I am loosing almost all of my gph. The whole system is just barely at a trickle. What do I do now? It has been working fine for months...now I don't even have enough water coming through the overflow to keep the skimmer full.