With what I've tested in the past you will have no issues hitting 300 on the sand. Top of my rock is in the 500/600par range around 12"under water.Tank does not have water yet so?
Should be fine as the light is only 5" from each end.
My structure for acros will be 48×22 in the tank so all light will be directly under the structure.
I am keeping 4" from glass to scape on all side.
I should be able to easily hit 300 par on the bottom at any area in the system with 2 50's.
I will map par, air only, and then when the systsm sees water in my build thread.
Take a look at this link.
Reef Breeders Photon V2+ LED Light: The Definitive Review
"You get what you pay for". We know that sentence all too well and our emotional response to the phrase is universally a negative one. But is it really fair treefs.com