I recently ordered this reactor for my 40g and should be receiving it today. In the description, it says it can run carbon and gfo, so I assumed I could use it just for gfo. After doing some research, in some BRS videos it says the reactor is too small for gfo only, while in the product questions, the site says you can use gfo alone. Before I put it in the water, I could use some advice from those of you who have one. Have you had success running only gfo?? Thanks in advance for your help!