I have mostly BRS biopellets, probably some ATB and Warner pellets still in there somewhere, in a Avast Marine MR5-18 reactor, at least that's what I seem to remember it to be, don't see it on the site anymore was a taller model of their MR5. I just shortened the tube a little like instructed by Dan for the biopellets and they move well. I get some tubeworms in my reactor but nothing like the concentration in Justins. Does the biopellet nozzle make that much of a difference?