Fangrui Product Details Biochemical filtration module: The figure is only a schematic effect, the actual filter element is not full in the dry state. The biochemical filter element has good water absorption, the state is dry when leaving the factory, the volume is small and rich in active holes, and it absorb water and when placed in a fish tank with water. Expiration reminder: refers to the function of the fish tank as a whole, not the function of a single filter element. Suitable for fish farming: Nitrate is produced around the 12th day of using the filter element, and the nitrification system begins to be established. After 30 days, the nitrate is stable at around 20-40 mg/L, which is suitable for fish to live in for a long time. 100% New Made of High Quality Meterial, Stronger And More , Improve The Appearance Easy to use,Easy to replace Free water change for half a year: 10 tropical ornamental fish of 7-12cm, fed twice a week, water pump 3 gears, no death within 180 days, ammonia nitrogen content 0-0.2mg/L after 6 days, n