Skimmer Help

[zanclus]

I have an aerofoamer 830 that I removed the becket from and converted into a recirculationg skimmer . I added an Orca pump for the recirc. I am reeded it with a 1"inch pipe (from my overflow) and the skimmer return is 1.5" My problem is this I allow water to enter the skimmer and adjust to about 1" below the "neck". Then whenI plug in the Orca pump the water level drops to about 4" deep in the skimmer and stays there . Could this be because the water entering is not under pressure? Any insights would be much abliged.. Thanks John