I know this is an old thread but I have the 72" orbit ic pro on a 165g and my montipora is about 16 to 18" down light set at 5" above water and hes struggling a bit. Still open and doing good but getting more lr to get him higher up but my hammers, acans, tube nem, long tentacle nem, mini carpet, zoas, ricordias,blastomussas, gsp,featherduster, and others are all thriving and doing great!! So they're not a bad light at all. Especially when you can accompany the light with their powerheads and pump. Which I have the pump and it doesn't amazing as well super quiet. You can also get the bluetooth adapter to control with your phone.