pH up is probably Potassium hydroxide.
Yeah, it will be tough- but worht it.
Flsuhing with very alkaline water is going to shock the plant, because you don't know about the soil already in the root ball. Just gently remove it and lay it on its side and then mix some lime into the soil- look in the 'organic' section for soil recipes and where they say 'peat moss' or 'peat', insert 'azalea dirt' lol. The ratio of lime to peat based soil is what you are looking for, not other additives.

I've done the exact same thing myself. Not with soil, but running orchid food and azalea food, assuming noobishly that 'acid' applied to ANY plant that liked a pH in the acid range... argh! lol