Good luck let me know how it works out. I had been debating buyin a nano remora myself for my 20g adn would love it if it were in fact upgradeable to a point.
I compared the sizes of the actual untits, the nano and the pro and the nano is like 2 inches shorter, an inch and a half more narrow and I believe 3/4 of inch less deep. So it's pretty much the same piece of hardware just a tad smaller.
180g Reef - 60g Rimless Reef -90G FOWLR- 125g Malawi Cichlids- 40b REEF- 34g Fresh Planted-working on- 20L FOWLR- working on
I have a mix of many different saltwater fish amongst my tanks, but I love my Tangs most of all.