As a purist, if I don't personally mix, test and retest the water that goes into my tank, it ain't goin in.
Maybe it's a guy thing.
Oh, by the way, the angel will be OK in your tank, IMO. Get a small one, 1.5-2.5 in. Supplement grazing tendency with algae sheets. Try to observe the small fish feed at the store before purchase.
I'd go so far to suggest a pair of tiny (1 in.) clownfish two months after the angel.
Not to forget... cycle and run the tank, as others have suggested, before any live addition, if possible.