Well, the tank had a lot of air bubbles in it. They were everywhere. So, I took the skimmer out and cleaned it. Let it out for about 3 days. The air bubbles in the tank are gone. I called the water department to see if they added anything to their water, they said they add everything as the water comes in. So, nothing new was added. She said it sounds like air is getting into the plumbing somehow. She said to scoop up the foam in a glass. If it all turns to clear water, than it's air in the lines. If it's cloudy, then it's something in the water. It all turned clear water. So, we took the plumbing off and redone it, resealed it. I can still see air bubbles in the tube coming from the tank to the sump. Oh, and took off the brass fittings also. Put the skimmer in today. It's still foaming, but not as bad. The cup isn't filling up with water...... yet. Should there be air bubbles in the line from the tank to the sump ?