I got a new protein skimmer for Christmas. The instructions are pretty limited. I have it set up as a hang on to the tank. I do not have a sump. Fish and reef in a 75 gallon tank. Turned on the skimmer and water flow is good but there is not bubbles or foam anywhere. Have made sure airlines are clear. Used the shorter connector to put water pump higher in the tank. I have no idea what I have wrong. Please help!