I've had one set above my 100 litre for over a year. Only 1%white and 50% blue.
I've then set up a 5ft 430litre and about 2 to go over it. Set it to the same amounts. The coral I've transferred over have done well. Considering its newly cycled.
I found that two wasnt quite enough so I added another.
So i decided to test the par today, now all the lights are up.
I've hung them 11 inches from the tank, with the bottom of the tank being 30inch down.
Testing just the blues with all 3 on 50% the amount of PAR was really high. Even on the sandbed where i was getting over 350par.
That would fry alot of what coral i have, the top was obviously much higher. The inconsistency of each light was also different the right hand light was getting alot more pare at the top then the right hand side. I think the spillage of light from adding one into the middle of the lights created a triangle either side of the middle light at a much higher PAR.
So I turned the middle light down to 15% and the two either end down to 30%. Whites I only have at 1% on the two end lights only. Middle light I've left as blue only for now, as the PAR was way to high.
First pic is blue only 30%
Second pic is blue and white. 30% and 1%
Theres a big range in PAR around the tank, even a few inches apart. But it gives you an idea of what the PAR is just at 30% blue and 1%white.
The pictures look more shady/patchy then it actually is as the window is behind me so getting decent pictures is hard.