Using carbon + GFO in canister filter for main chemical filtration

[20 gallon]

I was wondering if anyone uses activated carbon and GFO in a canister filter on their tank, how exactly they run it with their type of canister filter, and how effective they believe it its.

[bertoni]

Lots of people use carbon and GFO together. Canister filters can be fine, although not ideal, because they can allow a lot of channelization in the media. GFO can be very effective at reducing the phosphate level, and carbon can remove a lot of chemicals that tint the water, and likely some allelopathic compounds, as well.