Thanks ! Thinking about going with 4" DSB (Deep Sand Bed) this time of CaribSea Dry Aragonite Special Grade Reef Sand - a nice very white sand that not too small in size. This grade of aragonite is specifically engineered for plenum-type nitrate reducing beds or anywhere a deeper bed is called for. The pore water space created by precision grading also allows maximum pH support and dissolution of calcium carbonate. http://www.marinedepot.com/CaribSea...uariums-CaribSea-CS0020-FISSDS-CS0050-vi.html
