PAR loss w 120 lens?

[SnowManSnow]

So in adding a 120 wide spread lens, what percentage of par doe one loose? Has this been calculated yet?

This is for a XR30w (non pro)

Thank you for you help
B

 

[aqua1dude]

I think it cuts it in half but that's based on my experience. I run mine at 90%. I was running it at around 50% when I first got it because people said that the radions are so powerful. My coral started acting and looking much better once I kept increasing the intensity. I think 90 is the sweet spot for me. I wish I had a par meter to test with. This calculator may help you see what the PAR is http://www.aquaticlog.com/radion