Depends on the other features of your set up (sump or canister?) and the type of tank really. The skimmer will not contribute that much in the way of overall flow as much as a small contribution to aeration. The two 402's are about 270
GPH each so you would be considered at the low end for a
SW tank if this was a reef tank. Good water flow will always help in keeping a tanks ecosytem happy and healthy. If
FO or
FOWLR you might get by but personally I would up that with another
PH.
Cheers
Steve