Aclimatise them properly and they should be fine, stable PH is more important than the perfect PH. Don't just float the bag for fifteen mins and release them. Float the bag to equalise the temp, then open the bag and add an egg cupful of tank water, repeat every five mins for an hour, then release. I peg the bag to the tank side while doing this. This process will reduce PH shock. If the lfs you are getting them from is nearby, then they will probably already be in your tap waters PH, ask and if they don't know the PH, go elsewhere.
Jon