im not in the business of selling pounds so i dont know the exact numbers of a pound. but good to know. soil is fine, its forgiving and easy. but it also becomes a pain lugging empty soil to the backyard for years and running out of places to dump it. much easier to dump a reservoir of water down the drain. and also to bleach and re-use hydroton clay balls as your medium so you dont have to keep lugging bags of stuff into your location. things can go bad fast in dwc no question. before i got my slime under control (when i was trying to run a sterile reservoir) i'd go from healthy plants on track to yield amazing, to a plant that would never recover and only yielding a half ounce under a 1k. now i run microbes in my reservoir and that is a problem of the past thankfully. once your nutrients are dialed in and you're comfortable in dwc theres not much to worry about though.