NeolamprologusM

Hello all! First time poster here, I've had my tank set up for about 5 months now, have some rocks and driftwood with some plants on them for my electric blue acaras, I'm wanting to add more stones in the middle of the tank and I ordered some off Amazon (natural seiryu stones) I have some in my tank already, but I added them in before I had fish in the first time. Now, when I want to add them this time, will it raise the pH and harm the fish that are in the tank? Thanks!