My UNS 120 gal arrives next week 47"x 24" rectalular bottom. As I considered how much reef sand at 1.5" depth would be available to support a sand sifting star fish, nassarius snails and/or a sand sifting goby an idea struck me. The 2 pieces of large marco base rock and an additional medium base would sequester a lot of area needed by those organisms to feed and survive.
As shown in my pictures m, zi decided to put marco cement 1.5-2" rock under these bases, thereby lifting them to the height of the sand. Now the starfish, snails and microorganisms can utilize this vastly increased area and it will be living and functional.

As shown in my pictures m, zi decided to put marco cement 1.5-2" rock under these bases, thereby lifting them to the height of the sand. Now the starfish, snails and microorganisms can utilize this vastly increased area and it will be living and functional.

