That may be a little more pump than you need for the return.
I have an O.R. 3500 on a 75g & afterhead loss including my u.v., I have about 500gph on the nose. I have been very happy w/ it. I also have a 3500 sitting in my s.w. mixing can. & I have an O.R. 2700 n.w. on a diy skimmer.
NOW: I tried using an O.R. 6500 for a c.l. mounted external, I could not get that pump to stop leaking! There is an "adapter" that screws into the body for the outlet, then then barbed fitting srews onto that. Well, it kept seeping water between the body & the "adapter". The only thing I did not try was teflon paste. It even leaked w/ a fair amount of teflon tape on it.
So if you would like to still go for that pump, make sure it is internal.
Although it could have been a bad batch from the factory, but I do not want to take a chance myself.
Good luck,
Chris