My LEDs are in a canopy (which is painted white inside) with lenses to water surface at 12" and my tank is 22" deep. AI light spread at that height and 24" depth is supposed to be 24" X 24". With a 30" deep tank you may need them placed closer to the water surface. Or can cause shadowing. This is the reason some people say to get 4 units. So it depends on what corals you want to support and so on.
If you're trying to save money I would suggest you get 3, hang sideways and closer to the water surface and change out the 40* lenses to the wide angle lenses. Doing this also gets rid of the spotlight effect.
125g mixed reef Peninsula
If you're trying to save money I would suggest you get 3, hang sideways and closer to the water surface and change out the 40* lenses to the wide angle lenses. Doing this also gets rid of the spotlight effect.
125g mixed reef Peninsula