I did look at the video. I didn't respond because, I really do get tired of naysaying things, but sorry, I was not impressed either. A 30 lb yield from 16000W is really not that impressive and to me and to be truthful, those videos do not look like a 30 lb yield (more on that later). We are talking about 13.440 grams....so that is .84 grams per watt. Okay, but not impressive. I am like Hamster, you can say and do anything you want on You Tube. I know that a lot of what they put on there is ** and/or people trying to sell things.
I have never found anything anywhere that says that underlighting is good for a plant or increases yield and trust me many have tried it. I did not see any T5 underlighting, but whatever wattage he was using is going to have to be added to the 16000 he is running in HPS, which will put his yield at less than .84 grams per watt. Underlighting confuses the plant.
Okay, let's get back to his 30 lbs. None of those plants look like they are even going to yield 4 ozs.--a 4 oz plant is quite a large plant. But just for example say that each and every plant is 4 ozs. That would be 120 buckets that all produced 4 ozs. So, doesn't look like 120 buckets, doesn't look like 4 oz per plant, doesn't look like 30 lbs. Have you smoked any of his yield? This is truly the ONLY way to know if they are "fire" or not.
I know that everyone wants there to be some secret method, some secret ingredient, some special growing method that will outshine all others, but the truth is that there isn't. If you get 1 gram per watt, that is good. But that is a result of having a space that is dialed in and plants that are taken care of properly, not some secret additive or special growing method. You can try it if you want, but I would first advise on reading everything you can about underlighting and why it is not good.