Par Readings on new LED's

Nice pic John. Your PAR readings seem similar to my shallow 8 inch water deep frag tank under 150W phoenix 14K HQI’s and a pair of 420nm act T5s. I got 185-195 on the sand, 225-250 2-3 inches up from the sand and 350 near the surface. seems adequate, not overboard.

Hudzon makes a good point on PAR vs PUR. I found this explanation.

Our PAR meter(Photo Available Radiation) measures all light photon between 400-700nm. but for PUR(Photosyntheticaly Usable Radiation) it would be a bit lower.

I had thought about that lately, and had some ideas to judge the light. we can find the spectrum charts for mostof our lights, including LEDs. and most of them have little light beyond 500 NM. so i would guesstimate that the PUR might be like 80-90% of the PAR reading. maybe higher. Our MH lights make little in the green, yellow, orange and red spectrum. just enough to fool our eyes.

Sooooo… Your readings sound pretty fair. I think. because you balance the LED 450-470 blue with your good old 420 VHO actinics. The proof will be in the pudding. once the corals have a few months to readjust their percentage mix of chlorophyls A and B to make the best use your new light spectrum. all good things in reefing take time. Only the bad stuff happens over night while we are sleeping.