Product BIOCHEMICAL FILTER SPONGE: Filter sponge filters out debris, fish waste, food residue, fine particles and other impurities in a large area. The bio-sponge is washable and re-usable.​ Efficiency U-V LIGHT 253.7NM WAVELENGTH: Makes the green water clean and clear in 3-7 days, minimizes odors, clears cloudy smelly milky water. EASY TO CHECK IF THE LIGHT IS WORKING: ​To confirm that the U-V lamp is working, it is sufficient to check from the outside that the lamp is on without dismantling the machine.​ DOUBLE FILTRATION: The combination of Biochemical Sponge and efficient 254nm wavelength U-V lamp filtration maintains a stable aquarium state AUTOMATIC DAILY CYCLE TIMER: U-V lamp and filter operate separately. Set the lamp's working time once and it auto-cycles daily ALL-IN-1 DEVICE: Green killing machine, odor reduction, air pump, wave maker, aquarium filter. Clears cloudy water, It helps reduces water changes, saves time and costs EASY TO USE: The pump, lamp and sponge can be easily disassembled and assembled. Simple maintenance, housing indicator showing U-V working status WIDE USAGE: The adjustable water outlet is gentle to fish. Applicable for marine and freshwater tanks, vertical or horizontal use. The lowest water level was 3.5 in