I love sumps as well because they are really good for filtration and hiding all the accessories, but in this case, I would have to agree that a canister is probably the better way to go. For 365L, your overflow must be pretty huge to be able to accommodate the large pump which gives you the insane hourly turnover you're after. And what people don't realise is just how much math goes into a sump design! I only have a sump because it came with the tank, I would never be able to calculate everything right myself. Even after buying the tank/ sump, it took me one wasted pump to get the flow rate correct, I now have a pump which is too powerful for the sump overflow sitting in my storage because I couldn't find a buyer lol. Even if you wanted to cram 50 fish into that 365L, I'm sure that an FX5 which is designed for 1500L will be more than sufficient for you. Save the sump for your (eventual) huge tank - trust me, it will come. :thup: