HOB refugiums can work well. I have used them on several smaller tanks in the past, like biocubes and such. Have only had 1 actual name brand HOB refugium. The rest were made from aquaclear filters. Very simple to make those.
Many options out there for lights. Many are cheap and not much is really needed for such a small refugium. Have not used a HOB refugium in many years though, so I'm not sure what brands are really our there right now.
Refugiums also act as a good place to raise pods.
