I brought this thread back because I am still using PBP along with GH Ph up to get it to 6.5.I am thinking about not using the up at all.Does it kill the beneficial bacteria the way PH down does I just don't know.My mix is 1/2 ocean forest and 1/2 roots organic which has plenty of perlite.I use mycorrzae and worm castings in veg and mc and happy frog in flower.Thanks