There's a couple different measurements going on here: The 102 from post #27 is a lux reading for the xho's 12" under the led, that measurement was for Salty and is independent of the par reading taken for you with the Halides only at 4" above the tank in post #32.I’m so confused. I thought it was read 102 @ 12”? How did the par jump to 600 measured in the water at 12” + 4” to the the light? Am I really blasting 600 par to the bottom of my 20 gallon long reef?