Quote Originally Posted by dixiecowgirl
I did not change my sand......how can i check the propeller
With this additional information, I'd put my money on an incomplete Baqua conversion (and maybe a bad guage as well).

As Andy said, you do need to change your sand. Your sand is probably full of goop from the Baquacil that backwashing can't remove. That would explain why you're not seeing much pressure drop after backwashing but you are getting better return flow for a short time. Basically, the goop in the sand has made your filter super good at removing everything from your water which is quickly plugging up the filter. The only piece that doesn't seem to fit my theory puzzle is that your not seeing any further rise in pressure as the filter gets more and more clogged. That's why I still think you may have a bad guage (heck, it could be gunked up with Baqua-goop as well).

As for checking for air in the system, there should be a small valve on the pressure guage. Open that and see if you get a significant amount of air coming ouit before any water comes out. If you get water right away, you pobably don't have any suction side leaks.