Fluval bio media.

[Dannny]

Hello, could I add seachem matrix or any other bio media to the white bag that came with my Fluval fX4 and put it on top of the bio media that came with the unit?

 

[Fish Fan]

Can you? Absolutely! Should you? I don't think so. Those white biomedias have been know to sometimes leach heavy metals such as aluminum:
https://www.reef2reef.com/threads/a...e-frequent-waterchanges.1163945/post-14428908

I also don't think most reefers *need* extra bio media in their filters; the rocks and sand are the primary biofilter in a reef tank.

If you really feel that you need more biomedia in your canister filter, I would use good 'ole rock rubble, or plastic bio media. I don't think anything beats rock rubble for surface area, and plastic medias are inert, and won't interact with some medications like rock rubble can. I like plastic kitchen pot scrubbies from the local dollar store for plastic bio media.

Good luck!

 

[Mr. Mojo Rising]

I don't know why you have media to begin with, why want more? The rocks are the biomedia of a saltwater tank, nothing else is needed. If anything I would add some rock rubble or maybe a pouch of carbon. But if you want more media, it won't cause any harm, you can fill it up as much as you want.