8"x8"x4" Block MarinePure is designed to be a substrate for bio-filtration, specifically to target ammonia and nitrite removal (nitrification) and to minimize nitrates (denitrification). MarinePure is suitable for both freshwater and saltwater (marine) environments. MarinePure can be used fully submerged or in trickle/shower filters. It should not be used in moving bed filters. MarinePure™ Blocks are designed to allow the growth of both aerobic bacteria (near the surface) and anaerobic bacteria (internal). The growth of these bacterias allow for removal of ammonia, nitrite and nitrate. For optimum anaerobic growth, place in slower flow. Excellent for skimmer riser, but can be placed anywhere in the water column. MarinePure recommends one block per 100 gallons of saltwater system. 8"x8"x4" Blocks are great for larger aquariums. Just drop them in your sump or wet/dry filter. Features Light Weight - bulk density 0.3-0.5 g/cc High Surface Area - 1.3 - 1.7 square meter / g Open Pore Structure - 80-90% Open Porosity Chemically Inert Hydrophilic - Adsorbs water and stays wet longer Low Pressure Drop Unaffected by ozone Comparison Bio-Media Comparison Surface Area per Pack (Volume ft2/ft3) MarinePure Block 8x8x4 139,800 MarinePure Plate 8x8x1 139,800 MarinePure 1.5" Sphere 132,500 MarinePure GEMS 132,500 Plastic Bio-Balls 97 Sintered Glass Media 19,000 Assorted Ceramic Media ~22,000 Usage Recommendations Nitrification Recommended MarinePure amount for to eliminate ammonia and nitrite in an active filter, for a typical bio-load. Recommended Minimum MarinePure Amounts Tank Size GEMS Spheres Plates Blocks* 50 gal. 1 box < 1 quart < 1 plate < 1 block 100 gal. n/a 1 quart 1 plate < 1 block 250 gal. n/a 2 quarts 2 plates 1 block 500 gal. n/a 1-2 gallons 3-4 plates 1-2 blocks 2,500 gal. n/a 3-4 gallons 12 plates 4 blocks 10,000 gal. n/a n/a n/a n/a * MarinePure's thick blocks are designed to be used in passive systems to control nitrates. If used in active systems they will eliminate ammonia and nitrites (nitrification). Denitrification Recommended MarinePure amount to minimize nitrates in a passive filter, for a typical bio-load. Recommended Minimum MarinePure Amounts Tank Size Blocks in passive location 50 gal. 1 block 100 gal. 1 block 250 gal. 2 blocks 500 gal. 3 blocks 2,500 gal. 15 blocks 10,000 gal. 60 blocks * MarinePure's thick blocks are designed to be used in passive systems to control Nitrates (like live rock). If used in active systems they will eliminate ammonia and nitrites (nitrification).