I'm looking for 300 PAR below the light about 4” below the surface. Mounting height will be as needes. Since I'll be covering the full length of the tank, I was thinking of having them closer to the back so I could have lower PAR for LPS and deep water corals up front. I feel like two bars of 36 3-watt LEDs each will be sufficient, especially when the LEDs are all running at 100%.