2 T5's side by side directly on Top of = TOO much light over an Extra Tall Hood...

I measured the PPFD at the level of top of my clones in the dome with the Dome off. To my surprise it was over 400 Micro Moles! I say TOO much light for Clones. Conclusion: ONE T5 over my 12 Inch Extra Tall Dome is Plenty of Light! 2 Maybe after they have rooted but even Then maybe not even necessary! I believe unrooted Cuttings may not need anything more then 200 MM or MM2 however the PPFD is measured on my Photome app Light Meter...

plumsmooth said:

... Conclusion: ONE T5 over my 12 Inch Extra Tall Dome is Plenty of Light! ...

Click to expand...

1 is definitely better than 2. You can even use something as small as one single spiral 23W CFL about 3" from the top of the dome.

Update I had the diffuser setting WRONG on my Photome light meter. Would have been nice if they someone told me when I purchased this cheap piece of plastic for 20 Bucks. I have to choose manually a Plastic diffuser vs a paper one. Now it looks like it may still be a little bit more then necessary but definitely not 400 MM2 PPFD