A clean, white sand bed can make the difference between a nice reef tank and a great reef tank. Try cleaning that small space against the aquarium glass to remove the algal films that accumulate there to really make it shine; light bounces through the aquarium glass and gives the area some luminosity. Even though it’s popular to grow coral frags on a sand bed, remember to keep the sand bed clear if you want your display to really pop. Especially when photographing your tank, move corals off the sand bed and stir up discolored areas to make the tank look brighter. People often won’t notice the white sand directly, but will be impressed because “The tank is so clean”!