I've got a UVONAIR 3000, my grow space is about 10x10 and it does a pretty good job of eliminating the smell i would say, but near the end of flowering, it doesn't do the job, my plants just reek hella bad and it cant keep up with cleaning the air, and you cant leave it on all the time, i have it set to come on in intervals of 15 mins every hour. and theres still a pretty strong smell of weed after that, not as strong as it would be tho without anything thats for sure, during veg an early flowering tho, up til late flowering, it does a good job.