Bought a new filtrate sponge - got a leaflet about Filter media Cirax - anyone heard about these?

i don't have any idea of it since i never had use one.
sorry.

Thanks for taking the time Paul
apparently its a re-placement system for the sponges

anything that is phorous but could hold dirt is a good
alternatives. in my case, i get use to those discarded
stockings, synthetic fiber scarp from quilt making, volcanic
cinders, and grounded coral stones. it works for me well.