I have a 75 gallon aquarium fully established, had it for almost 3 years with 3 bichirs, a black ghost knife, a tire track eel,a elephant nose fish and a pleco. I was wondering if I add 4 pieces of driftwood 2 large and 2 medium will it effect those fish by lowering the pH to much or any other problems? I know the pleco i have likes wood but other than that not sure.