As Brian said, it would be best in a single reactor. If you decide to try the dual, you would have to leave the first chamber empty(including the insert) and have a strong enough pump to cause the pellets to tumble, and you'd have to get a bio-pellet insert for that chamber. I started out using a single BRS reactor with the pellet insert, but ultimately bought the RO BM 110 pellet reactor.
Are you using the dual reactor for anything right now?
Are you using the dual reactor for anything right now?