flow questions

[mytank90]

i just got a new 120 gallon tank with a 33 gallon sump <my first ever drilled tank>and am wondering on what size /flow of sump pump i should look at getting .i want to try some sps coral in new tank .right now i have a little giant 500 that flows roughly 500 g/p/h /tank has 2 returns in it .also would 2 koralia 4 be ok ? thanks