Improve the Water Quality: Suitable for seawater, fresh water and water tank Reduce the Fish Mortality: Great to filter water, give the fish a better living life Durable and Reuse: Cleaned once a month, no blocking, no deformation, can be reused after cleaning The bio sponge filter able to be use in marine, freshwater and planted tanks, which you are able to cut to the size you want which suits your filter. The experts according to experiment concluded that the molecules hole size and softness is best suitable to develop the best for bacteria. The bio sponge is able to dissolve waste of fishes and also improve water quality then will reduce death rate of fishes in tank. Monthly once washing of bio sponge filter by using running tap water to clean, after washing and cleaning its shape will remain, the hole will not be blocked by dirty particulars, it can be reused continuously. Size Available: The size can be cut freely as you need Decrease the frequency of fish tank water changing Model: XY-1812 Bio Sponge Dimension: 34*12*2CM