This is my first post on TropicalFishKeeping.com, so I hope I'm in the right place. First of all I have 4 tanks, a 30 gallon long, and 30 gallon tall, a 75 gallon, and now a 165 gallon. As of now my 75 gallon is full of Malawians, which I am using common aquarium gravel. I am getting ready to move these africans to my 165, and I am going to use white sand instead of gravel. My question is, I have a 2 gallon bucket of crushed coral, when I say crushed coral, I mean these are in 3/4 to 1 inch chunks, I am considering burying the crushed coral under the sand along the back wall of my tank. Other than the africans doing a lot of digging, would this be worth my effort with the coral buried in the sand to help work as a PH buffer?