It sounds like you have a water pump bearing or alternator bearing or an alignment issue. (I take it no power steering pump)
I'd check alignment of all three pulleys in relationship to each other using a metal straight edge or a yard stick. Also inspect the alternator if the nose appears tipped down or up. You may want to do these same checks again once a belt is installed.
If you don't mind sacrificing another belt, wait until it starts squealing and you're at a garage or home. Then cut the belt off and check the alternator and water pump for binding.
The tension should be 1/2" deflection of the belt when pushed with one finger in the center of the run from the water pump to the Alternator. Too tight and you smoke bearings.
Eliminate Belt Noise by Servicing the Entire Belt Drive System