Well, most of the captive rearing reports are on Aplysia spp., but the good news is that Dolabella spp. are thought to be very cosmopolitan in their algae eating preferences; that is, they are not believed to feed only on one species or genus of algae. This means that any macroalgae that you have in your tank, provided that it isn't a noxious sp., will probably be eaten. The bad news is that Dolabella spp. sea hares grow rather large, and in a nano reef tank, it is unlikely that you are going to be able to support the sea hare for any length of time. I don't have a problem with people supplementing the diet of their sea hares with things like nori (NOTE: this only works w/ sea hares, and not w/ Sacoglossans, aka sap-sucking slugs), but I don't think it would be wise to try to keep a large sea hare alive on nori alone. It may be best to hand the sea hare over to a friend who has an algae problem once the sea hare has eaten all the available algae in your tank.