Thanks for the positive comments guys, im really pumped about this new setup. As far as rock, i had about 60-70 pounds of rock in the 138, and then purchased about 225 pounds of marco rocks. As far as sand, believe it or not i only used (4) 40# bags of the carib sea seaflor special grade reef sand. the depth is about 1.75'' throughout. to me it's the same depth as the 138 which was enough to keep rocks in place as well as allow all of my wrasses plenty of space to bury themselves at night.