For freshwater aquarium use: Use one Xport Bio Block for every 20 to 40 U.S. gallons (80 to 160 L), more for heavy bio loads. Rinse material well with purified tap water. Seed using Florinbacter or Florinbacter Clean by placing in a plastic container, filling it with aquarium water, and then adding the full recommended dose. Stand overnight and then add to your system. Discard soak. Use fine filter floss to prevent clogging with organic material and prevent churning. Do not fluidize or allow to churn. For maximum results, also provide a good carbon source for growing bacteria, such as Brightwell FlorinAxis. Caution: Keep out of reach of children. Not for human use or consumption.