Here is the response i got from Kessil:
Thank you for presenting us with this opportunity.
We currently do not have official PAR measurements. There are people who have done so and I can include a link. What we have found is that the value even between units that perform the same differs greatly. We also see that different meters have different results and some do not measure UV or near UV. This is one of the reasons we spend over 1 year of independent testing on reef tanks, and we allowed our local stores in the SF bay area to test first hand as well.
I hope this link helps and feel free to let me know if you have any questions. I get a lot of feedback that Post #10 & #114 are very helpful to end users. http://www.reefcentral.com/forums/sh...2040877&page=5
Oddly enough, i found post #71
to be more relevant.