Well I have Angels, and guppies; great combination! As long as you don't want guppy fry
My guppies are now little more than live-food providers, and the angels will get the fry no matter what (I used 2 breeder nets at one point, a big 'net' style one, with a hagen plastic one inside, angels kept getting into the big net... sucked the fry out the bottom of the plastic one... Smart lil guys!)
Angels appreciate salt on occasion also; salt has nothing to do with acidity...