2kg bag of Alfagrog E25 Ceramic Filter media for Ponds and Aquariums 

Alfagrog is ideal for use in any biological filter system. It is very popular among koi keepers and commonly used in multi chamber filter systems

Replacing plastic filter media with alfagrog will massively increase the biological capacity of your filter.

Alfagrog is porous foamed ceramic material, which is lightweight, strong and inert.

Its high surface area makes it the natural choice for colonisation by micro organisms in biological filtration systems resulting in cleaner water