On my old 300 I ran external, I had the real estate under the tank. I ran Reef Octopus both times, a Super reef 5000 and then an XP 5000, only difference was cone body. They both had bubble blaster pumps and really were set it and forget it, I just teed off my return pump to feed them.
If you want internal you could run the Elite 220 and its a dc pump with a good warranty.
I have never run one of the Nyos yet but hear good things.