I had a thrip problem. The only way I could get rid of them was a Hot Shot No Pest Strip. I would put it in the tent during lights out, turn the fan down low, and let it sit for 5-6 hours. I did that every night, every other night for 7-10 days to cover the entire lifecycle. Haven't seen one since.
I put the strip in a zip-lock freezer bag to keep it if I need to use it again. It's really toxic, I wouldn't over use it. Some people might not use it at all. But, I got tired of trying to control them with "nice" stuff. Next time, I won't wait so long. On first sight, I'll go nuclear again.