Tty....holy shit you gotta be kidding me (i know your not).??? Damn. It makes sense in an ecological way i suppose but damn man. The Dutch government back in the day told the entire greenhouse industry no more open non recovery dtw and they had to do something about all the spent rockwool accumulating in landfills. Dont know how they switched that one up but I do know the big flower fruit and veggie growers in Holland have to recirculate now. U.V. sterilzation and what not. But this no dtw in Colorado rule is definitely news to me. Lets be honest...drain to waste isnt the most ecologically friendly way to grow hydroponically. If you use a bigger pot...keep ppm's on the low side..and keep it wetter than a normal drip to waste (not as much dry down between feeds) you can get away with a no runoff top feed setup and still have substrate balance. Big or small. In Colorado..looks like a grpwer has no choice. I wonder if this applies to straight ag crops as well now??? There has to be some bigger dtw rockwool and cocopeat greenhouse tomato growers that dont like the new rules if it does.