Don't forget to check around your home supply stores when shopping as they make plastic trash cans in almost any size and shape you want. If pure grow space volume is the issue, square is generally better than round allowing more efficient side by side stacking. I have a number of work cubicle trash cans in the 9x9x14 variety. Pop drain holes and go.
I also make these assemblies from my empty 2.5gal water jugs as I own them already and are emptied on the hydro unit. Just cut the valve end out of jug, pop drain holes and paint to block light. If you look close you will see two bailing wire wraps around the side grooves as these can be mis-shaped under load when filled. With that extra support I have never had an issue yet. I then use the window planter style under tray as it will hold two of these units nicely. Although rectangular rather than square, I can line these assemblies right up in closet for good total count and still get to each for individual care or plucking males etc. I'll try to drop a photo instead of all these words, see if I can get it right.
