Fluval BIOMAX Biological Filter Media - 1100g

The Fluval BIOMAX Biological Filter Media is 1100 grams of porous ceramic rings — the surface the bacteria live on, which is what actually makes an aquarium filter a filter rather than a sieve.

Key Features

• A complex pore structure rather than a smooth surface, which is what gives a small volume of ceramic an enormous area for bacteria to colonise
• Houses the two bacterial groups that convert ammonia to nitrite and nitrite to nitrate, which is the whole basis of a stable aquarium
• 1100 g is a large bag — enough to fill a canister basket with some left over
• Fits any filter with room for loose media: canisters, hang-on baskets and sumps
• For use in both freshwater and saltwater aquariums
• Made by Fluval, the aquatics brand of Rolf C. Hagen, which has been building aquarium filters since 1975

Using It

• Rinse it under running water before the first use to wash off dust
• Put it in after the mechanical stage. Chemical and biological media work on water that has already had the solids taken out of it
• Never wash biological media in tap water and never replace it all at once. Chlorine kills the bacteria living on it, and changing everything together restarts the cycle
• A liquid test kit for ammonia, nitrite and nitrate tells you more about a tank than anything you can see

The Part People Get Wrong

• Never wash biological media in tap water and never replace it all at once. Chlorine kills the bacteria living on it, and changing everything together restarts the cycle
• Replace no more than a third at a time, and leave at least a month between changes
• Rinse it gently in a bucket of tank water when it clogs. It does not need to look clean — the brown film on it is the point
• Biological media does not wear out quickly. It is replaced because the pores block, not because it stops working
• A new tank has no bacteria in it. Cycling — running the filter for several weeks until it processes ammonia and nitrite to zero — has to happen before fish go in, or they sit in their own waste while the bacteria catch up

Good To Know

• This is the media to move across when you upgrade a filter. Bacteria on old BIOMAX will seed a new filter and save you a cycle
• Nitrate is the end product and BIOMAX does not remove it. Water changes do
• A tank with a big bacterial population is a forgiving tank. This is the cheapest thing you can add that makes a real difference
• A liquid test kit for ammonia, nitrite and nitrate tells you more about a tank than anything you can see