They seem to make my plants very sticky and smelly.
I'm running mine on a cycle of 5 minutes every 2 hours. I'm growing autos and have my main light on 24/7.
But I mounted mine to some cpvc tubing and have them sitting on my main light.This way it's easy to move them if I need to.
This is my second grow with them. My last grow my plant was almost gooey. So they are doing something.