I'm having an extremely hard time deciding between black and natural colored sand. I've read that the plants and fish color "pop" much better with the black. I know its a personal preferance but I've never seen a tank with black substrate. Do the fish look a lot less colorful on a natural color substrate? Does a lighter color stress them more? And how much should I use....1.5 inches in depth? Its a 29 gallon. All opinions and comments are welcome