absolutly DO NOT keep it sealed...it WILL rot! and don't give it TOO much air either it needs to stay moist to grow.....
and unless you want to concoct a contraption to automatically mist the grain and some way to automatically stir it, like a 50 gallon plastic drum, and motor turning it or something, with misting....
honestly it works just fine for me using my spare bathtub that's not used for anything else....(it's a vanity tub, figure this a good use for it?)
i do make sure to mix the grain bed which is about 2"'s deep up to let the lower kernels breath, but i do it by hand maybe once twice a day...
and i eyeball when the barley starts slowing down on growing, and needs a quick watering to finish it off...becomes more an art, when it's at the almost done...to water or not water...
just a little more growth! i usually opt on the more growth...
edit: but i find the barley expects a dry spell and won't die, and just conserve energy for a while before sudden death happens...
edit 2: i mean if you want to out do me, if you're crafty enough to stir the barley while something like this was running?
https://www.daraz.pk/products/mist-fan-system-complete-kit-i144332404.html
just get a fan speed controller for the water flow, so you can dial in how thick the mist was?
(just keep in mind you'd be aproching pro levels at that point! it doesn't need to be that hard
)