and now my current experience:
6x T5 à 80Watts each (supplemented with individual reflectors - one per tube) - 6500K/3000K ratio 2:1
3 inches below: 5973
6 below: 4600
9 below: 3500
12 below: 2400
15 below: 1570
4x T5 à 80Watts each (no individual reflectors) - 6500K/3000K ratio 3:1
3 inches below: 3900
6 below: 2600
9 below: 1500
all meassurements done below the central part of the lamps!
well, I think I have understimated the power of these tubes
need to find a solution soon, before I start sending invitations for Orchids-BBQ!