I just snap a picture of the tank and assign a number to a location that I reference in an excel spreadsheet. Then I toss relevant notes at the end for details.
Notes:
1) Location 3 is centered under one light right to left but not front to back (even with top of rocks on the back side of these two corals).
2) Locations 6 is very close to the center of the tank left to right (a couple inches closer to the front glass front to back).
3) The Kessils are centered over the tank front to back and 18.5" apart (9.25" left and right of center).
4) The fixture is mounted 6" above the water line.
5) There is a bit of light spillage on all viewing sides of the aquarium so the lights could be mounted closer to the water to increase PAR values without losing coverage.
6) PAR values were measured on our local clubs Apogee MQ-500 with full spectrum sensor using an immersion correction factor of 1.32.
7) Standard 75g Marineland aquarium 48"x18"x21" (LxWxH).
8) Two Kessil A360WE (60% color) with four 54w T5s in a 48" Aquatic Life Hybrid fixture (2 Blue+, 1 AquaBlue Special, and 1 Purple+)
9) 16" side rails mounted on the Aquatic Life to narrow the unit 2" from how it ships.
10) MP40s set to feed mode while measurements were taken.
11) Return from sump remained on but has fairly low flow and doesn't agitate water surface much.
12) Hybrid column represents the Aquatic Life fixture with only the T5 on.
13) LET column represents past results of the LET T5 retrofit kit for comparison.
14) The LET retrofit had two 54w T5s (1 Blue+ and 1 Coral+ at the time).
