I would shoot for a turnover of about 8-10 times an hour. You could get this a few different ways. You could get 800 gph with two Emperor 400s. I use 3 400s on my 150 and there are no issues. Some people like canister filters...I personally like the convenience of the power filter. As long as your water changes are done properly, you should be fine with a couple of high-end power filters.
Let me know how it turns out.