If you have two foam pads, you could put gfo
at the bottom of the reactor canister, place a foam pad a couple inches above the gfo
, then carbon, then another foam pad right above the carbon so it doesn't have room to tumble. This is how the BRS deluxe reactor (single canister) works. It has been working really well for me. I can adjust the amount of tumbling for the gfo
by adjusting the intake valve, but the carbon doesn't tumble because it is held in place by the pads.
You should be able to get pads cheap from any hardware store. Just make sure it is porous and that you cut it so that it fits snugly into the canister. Or just buy the BRS reactor. It's pretty reasonably priced and looks clean.