Adding GH booster isn't going to have any affect on your KH or pH, just GH. Some people add sodium bicarb ( baking soda ) to raise their KH. Brighty K, which is an ADA potassium supplement, is derived at least in part from potassium carbonate and will also raise your KH. I would imagine that following the dosing recommendations for Brighty K would offset any affects on KH that Aquasoil would have since the ADA line seems to be pretty well thought out.
If I were you, I'd PM Frank from ADG ( screenname is Francis Xavier ) with your questions.