I'm in the process of replacing my Aquarium with a larger one. While preparing to make the change, it occurred to me that I think I have way too much gravel in my tank. It's probably 2 to 3 inches. I'm planning to not use nearly as much in the new tank. Just enough to cover the roots for the plants. Is this a mistake? Even though I gravel vac regularly, it was shocking how much junk was down in that substrate. The tank is only six months old.