I have always lighted my refugium 24/7 to prevent the macro from going asexual. Seems to work fine--at least over the last 5 years.
I haven't seen/looked for any studies re: the benefits, if any, of using inverse lighting to minimize pH swings, or to what extent inverse lighting would stabilize pH overnight. I've seen that approach discussed before, but I just always used 24/7 since I thought the discussions of macro going sexual seemed like that would be a real pain.
