Aqua Natural Substrates All Aqua Natural gravel or substrates are 100% natural, sustainably sourced, triple washed and kiln dried. Our meticulously graded gravels and sands are the perfect natural substrates for any aquarium including planted tanks. Our high quality products create natural beauty combined with large surface areas for beneficial bacteria colonies and easy cleaning. Nitrifying Bacteria Pack contains bio activated live nitrifying bacteria to either use as a primary substrate or mix with substrate for a healthy aquarium. Contains a patented blend of live nitrosomas and nitrobacter bacteria which break down and convert harmful ammonia, into nitrates. Directions for use: PRIMARY (not mixed with Dry Substrate) Usage Calculator: Use 1lb (450g) of Bio-Substrate for every 1 gallons (3.8 litres) of water. - DO NOT rinse before use. - Spread substrate and fill with water slowly. Avoid stirring up the substrate. - Once the tank is filled, start your filter. Any cloudy appearance should clear over time. MIXED (mixed with Dry Substrate) Usage Calculator: Use 1lb (450g) of mixed LIVE Bio-Substrate and DRY Substrate for every 1 gallons (3.8 litres) of water. Mixing ratio is 1:4 (1 LIVE to 4 DRY). - DO NOT rinse before use. - Mix Bio-Substrate and Dry Substrate thoroughly. - Now spread mixed substrate and fill with water slowly. Avoid stirring up the substrate. - Once the tank is filled, start your filter. - Any cloudy appearance should clear over time. LIVE nitrosomas and nitrobacter bacteria are harmless to marine life. Use with any corresponding Dry Aqua Natural