Bubbles!

[kank]

Set my tank up a week ago after a three year hiatus. Everything was going fine until couple a days ago when I added rock and then a bubble frenzy began. Looks like these bubbles are coming out of my return line. I thought they were maybe being caused by my overflow but the bubbles going through my overflow are being caught in a filter pad. Is my pump possibly bad? Need some advise as I have never had this problem before. Help!

 

[bang guy]

This sounds like cavitation. Try an experiment, slightly restrict the return from the pump and see if the bubbles stop. See if there's anything restricting the flow between the sump and the pump.
A couple other possibilities are a pinhole leak in the plumbing between the sump and the pump (obviously if the pump is submerged in the sump this isn't the problem), low water in the sump allowing the pump to create a vortex & suck air, a leak in the pump casing caused by dry rot.