If the angels were acclimated at the LFS to your water supply, or were bred locally, you might not even have to worry about it. Find out what they came from and compare it to yours. Keep in mind that your KH (carbonate hardness) will interfere with organic ways to lower pH, such as peat or Muriatic Acid (some discus keepers use Muriatic Acid).
I personally use peat in the filters and the changewater for my discus and angels, as well as live plants.
remember that what's listed as "best" is an ideal situation, but that most angels are bred in less than ideal...
try www.angelsplus.com for more on water issues....great site overall, and might help you decide if you want to go the lowerpH route.