I see a lot of people turning incredible turnover rates on here and I started questioning my set up. Currently on my 90 gallon I run a Marineland Penguin 350 and a Fluval 205. I am moving 530 gph right now turning the tank over almost 6 times an hour. Is this going to be enough when my fish get fully grown? I don't plan to modify the current stocklist unless something really good comes along. Any suggestions as to whether it will be necessary to upgrade or add another canister filter later.

How would spiking nitrates justify a filter upgrade? Most would just do regular water changes to keep nitrate levels under control.