The BRS reactors come with a sponge, well 2 actually, could put on on the return end as a safekeep. Also, Seachem recommends running it in a media bag, it's stated after they also stated that it can be run in a reactor, so I guess i was a little confused... Should it be in a media bag IN the reactor? I guess it wouldn't hurt, and would hold it together, as it did also state to not have it tumble on itself... I should have the MJ1200 tuned wayyyy down for this attempt eh??