You should be fine w/ 1 MP40, but if you'd like to add additional flow, check out the Tunze 6095. It's a new pump, but it's awesome. I have one on my 90 (LPS and Zoanthid dominated) and couldn't be happier with it.
And no, these pumps don't suffer from the 'advertised vs reality flow' "Issues" that the 6105 and up had. The nanos never had that problem, and the 6095 is a new pump.