When you are thinking of lighting, don't think of it like you would older style bulbed units. LEDs penetrate water amazingly well. At full power it will easily burn and kill coral if not properly acclimated. These things are extremely powerful. When I was running my Gen 2 Radions, I never had them over 60% intensity if I remember correctly. I'd tell you what my AI are currently running at, but a phone crash
led to me loosing my settings...any screwing with it will change things up so I've been letting sleeping dogs lay...but it by far isn't higher than 60% intensity. 20 tall really is nothing for
LED water penetration.