You sure can.and also its a personal choice both using carbon and using a filter sock. I use both. Some use nothing.
I use a brs 2 chamber reactor. 1 for gfo the other carbon. They are pretty cheap but for years I just dumped a mesh bag with carbon in the flow of the sump.
Like I always say you can make this hobby as cheap or as expensive as you want.
I run about a 1.5-2 cups in a reactor off my return manifold on my 125, change it every 2-3 weeks. Filter sock would be easy though, just change it when you change the sock.