protein skimmer

Hey guys got rid of the uv sterilizer and finally got a protein skimmer. Problem is I bought a cheap one from ebay, cannot even remember the name, rated for 150 gallon tank. Hooked everything up, put the pump in the sump and mounted the skimmer on back of tank. Got about 5 feet of distance from the the pump to the skimmer. I see micro bubbles forming, but I cannot get the water level to get all the way up to the cone. I have the valve from the pump wide open. Could it be that the pump is not strong enough.