Recommend me a pump

What are your overflow(s) rated at for gph? From there you'll need to look at the mag pumps and have one match the flow rate back to the tank after compensating for head loss. So if your draining 1200 gph vs 600 you'll probably want to go larger. I have a 9.5 on my 75 with a 600 gph overflow and it works out really good. There is a little extra pressure that I have to divert to my refugium because the pump does outperform the overflow a little with the head loss. But if you have a 3 ft head loss the 9.5 is around 800 - 825 gph at that point.
 
Cheech it works really really well. It took me several tries in plumbing to get it right. (Like 60 bucks worth of pvc, joints etc but I got it right finally :D) I put a gate valve on so I can better control the dial in of that branch off. I tried a ball valve but they are sooooo touchy compared to a gate valve. I also branched off with 3/4 (because thats the gate valve I could find) vs the 1". It really does work like a charm.
 
Well if you want a Danner Mag pump here is a list.. But all of these are submersible only.

magdrives.jpg
 
AquariaCentral.com