There is a rule of thumb for high tech tanks that says you should buy a canister filter rated 10x your tank volume (because the real flow would be aprox. 50%). So you should buy one or two filters to have 3,000 liters per hour, BUT you will see plenty of people with large tanks using less flow. My advice is "buy the better you can afford", at least buy a reliable filter for which you can easily find spare parts if needed.
Jordi