The EcoBio-Block EcoBio-Stone with Beneficial Aquarium Bacteria combines beneficial bacteria and a great place for them to grow to deliver beneficial biological filtration.
These are made from highly porous Japanese volcanic that are also full of minerals that will provide plenty of surface area for bacteria to grow. But, it takes it a step further and is embedded with beneficial natural bacteria spores that only germinate when organic waste is present in the water.
The bacteria aids in breaking down waste to accelerate the nitrogen cycle. Calcium and trace minerals are also slowly leeched into the water from the stone to create a healthy environment that requires minimum maintenance.
They come in two sizes — small and medium — and retail for $13 for the small and $21 for the medium. A small stone treats 8 to 16 gallons and medium stone treats 15 to 40 gallons. You can easily add more as needed if you have a larger tank.
Just put these into the aquarium, or tuck away in a filtration chamber or sump.