Bio balls are like small plastic houses for nitrifying bacteria. That good bacteria in your tank converts ammonia into nitrite and then nitrite into nitrate. The unusual, open-structure pattern that is found on bio balls actually increases the surface area of each bio ball. bacteria likes to cling to the surface of objects and these bio balls have been designed to provide as much surface area as possible for the bacteria to cling to.
Bio balls sit in your filter. As water passes over these balls, the nitrifying bacteria filters your water, removing ammonia and nitrites – dramatically improving the water quality. They work best in your canister filter or sump.
How many bio balls do you need?
A general rule of thumb is 45 litres of water per litre of bio balls. Oty 200 of 42 mm diameter bio balls is about 14.8 litres which is enough for 665 litres of aquarium water. While adding fewer bio balls than recommend results in inadequate filtration, there is no harm in adding more.
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