question about emporer 400 mod

[Kevccoy]

I am thinking of trying this:
Emperor 400 - Power Filter Tricks
Matrix rock is kinda pricey correect? what else could be used equally affective? any ideas? and what do you think of this mod with just some sponges in front or behind it? or should i continue to use the replacement filter cartridges.

 

[Greenmaster]

Matrix rock is not that bad... you should use them or something that is similar (would also be a similar price) It is a porous ceramic. Most filter company's put out some kind of ceramic bio media. Another thing you could do that would be simpler would be to put an air stone in the bottom of the two sides and then fill the two sides with the bio media. It would essentially be the same thing but it wouldn't remove your carbon. (carbon helps to take smells and chemicals out of the water. It also helps with water clarity)