There are a lot of variables ranging from the kind of pumps you're using to your aquascaping, to the kinds of mixed corals you are going to have.
Will it be SPS dominated, LPS or softies?
I keep mostly Acroporas so for me I would use a minimum of two Koralia evo 1400's.
In my 210, right now I have two tunze 6105's and two Jabeo WP-40's for up to a 100x turnover when all of the pumps are on.