We have a 150gal with 6 inch deep sand bed and 55 gal refugium also with dsb. All 300-400lbs of it was collected by my wife and I,brought home submerged in buckets ad coolers from the gulf of mexico. Also tons of live rock,hand picked each piece while snorkeling. Probably the best thing we did. Not much of a new tank cycle. Almost 3 years later,tons of sponge,small clams in the sand bed,free clean up crew.The sad bed has stayed white. Even filled with ocean water (at first),parameters a little off. Just make sure you collect somewhere of the beaten path,not the popular beach. Also the sand was collected while underwater,not dry up on the beach. Only thing it was bad for was our backs.