Ive done it before with harder carbon, filter pads in the reactor and a final filter sock. Just make full use of the GFO as it is the much more expensive medium.
Yeah, medium is singular, media is already plural. Do not use FAKE MEDIA, it will not work on half the people. Hehe. Easy mistake to make as they call them a mediA reactor, but none were actually designed to run more than 1 medium at a time. Because if the call them a filter medium reactor some baller would demand extra large, XXL for the big boy tanks. But I digress...