Confused to what system my friend is using??

My friend gets huge yields every time from his grows 20+ oz's every time but the system he uses ive never seen anyone else use i dont think he has a huge plant pot 70-80 liters makes many holes at the bottom of it and puts it in a huge tray. he fills the tray up with water and the plant pot full of clay pebbles sticks his clone in then puts the water pump in the tray and a hose leading to the top of the plant pot where it constantly waters. the whole thing is on the same timer 600W hps fans and pump are all on and off at the same time so the pump is of for 6 hours a night but on constantly for 18 hours a day? Im confused how this works as i though he would get root rot or root drying? but never he constantly gets good yields? :s

If he's getting 20+ OZs from one clone, I'd be interested to know myself. Otherwise, shenanigans.

You have to weight it dry or it doesn't count.

Everyone lies about their yeild.

It is dry i buy it from him ive seen his plants there like trees i will get a picture on the next yield to prove how big they get. I just want to know if anyone else has used that method in growing....btw he has been growing for over 20 yrs and he does veg them for 7+weeks