I have a couple Reptisun 10.0 T5 22" in fixtures like the guy in the YouTube. I used them in flower over two plants in my small tent. I am not sure if the helped or not but I plan on hanging them back up within a few inches of top of plants again when I flip my current grow in about 4 weeks.
Some where around here was a guy claiming some particular T5 tubes were giving substantial readings at 3 FEET. I'm subbed.
Here is the brand mentioned.
I can't find the product talked about but that is the brand. I have the actual tubes link bookmarked at home.
I find the 3 FEET distance claim something that needs some proof but it's interesting. No hijack ment.