Water not draining into sump

I have a 90 gallon drilled tank that has been up running perfectly for over a year now. Today I was moving stuff around and all the sudden the water that is supposed to be coming out of my drain hose slowed drastically. So now the water level in the return area of my sump is very low. I don't know if the drain plumbing broke siphon or what but I can't figure out how get the water flowing down the drain pipe again. Any suggestions?



I tried moving the drain plumbing up and down and unplugging the return pump and plugging it in again to change water flow but still nothing.



Help!!