If you want to use this as your primary filter consider this:
You need to have mechanical, biological and (sometimes) chemical filtration.
The Magnum has a media container that you can use in several ways. You can fill it with biological media and use the filter sleeve for mechanical filtration. The sleeve, however just filters coarse material and does not do a very good job in removing fine material.
You can use the micron filter which will give you outstanding water clarity, but will have to be cleaned in 4-7 days as it clogs rapidly. Also no Biological Filtration.
You can use the media container with floss and the filter sleeve-almost as good as the micron filter.
If you want to use this filter as your only filter, I would buy the Pro kit which includes the BIO-Wheel Pro 60
which would give you your biological filtration along with mechanical filtration.
The times in which you would need to use charcoal, you can fill the media canister with charcoal and use the filter sleeve for a few days.