still i have had that set up and it really isn't that strong plus plants producing buds the size you're saying roots will clog that entire system you would have to constantly trip which in doing will end up with less yield, no matter what your lighting was your system would not support, im not no expert grower but ive had a few tries and everytime i try something new and ive tried what your saying and its not that outcome you would need 30 gallon pots for thos 15 plants your talking bout to produce those yields