[bertoni]

I tend to be cautious, so I would light one refugium on reverse lighting, and see how that goes. If that's not enough, I'd light the other. That's probably excessively cautious, but those pH levels are safe, so I'd prefer not to rock the boat very much.

Have you checked the aeration capacity? It's very rare to have an aeration problem, but checking quickly to make sure that there's no surface film, and looking at the skimmer (if present) to make sure that it's producing a good stream of very fine bubbles tends should only take a few minutes. I kept a good rippling motion on the water surface of my tanks to make sure that aeration was okay.