Hey, it depends on the system you're running. If you're going with live rock then that will be your main filtration system - Live rock holds all the bacteria your system needs in order to process the fishwaste etc.
However, if you want some extra filtration, a sump with a refugium is (in my opinion) the best secondary filtration you can find. It's better than external canisters for several reasons:
- It increases the water volume of the system and thus chemical changes happen alot slower
- You can put a heap more stuff in it, for example the heater, skimmer (which is another way of filtering)
- You can cultivate macro algae (cheato for example) which reduces nitrates(? Sorry, either nitrites or nitrates, I forgot
)
- If you add in a deep sand bed that further helps the nitrogen cycle complete by conveting nitrates into nitrogen gas
Canisters also have to be cleaned fairly often so that they don't get clogged and/or produce heaps of nitrates. However, if you're dead set on using canisters then I think you'll need to get another of similar specs in order to filter a system with a medium bioload if you're not using live rock. If you're using live rock then that canister should be fine, just be sure to clean it
As for media, I'd recommend filling a chamber or two with live rock rubble, I don't use canisters so I wouldn't know the general outlay, but if you can fit a small sandbed into one part that'd help. And using activated carbon or ferric oxide with biweekly changes should help
I think a protien skimmer for that size tank will also be a good idea - protien skimmers take alot of the organic compounds out of the water before they can degrade and cause problems, unfortunately I'm still sketchy on what skimmers do but I'm sure someone else can fill you in!
