No water coming out of aid release valve

[xray328]

Hey guys. Up until now when If open the air release valve ( is that the right name for it?) on top of the filter it would shoot some air out, then blast water. But now a little air continuously leaks out and no water ever comes out. Any idea what would cause that? Pump and filter seem fine otherwise.

 

[JamesW]

There is probably dirt and debris clogging the air relief valve. Typically, the debris will often contain tiny bits of lighter-than-water debris, like Styrofoam, as that tends to float on top of the water as the tank fills with water.