I've seen and heard a lot of really good things about hydroponics but I haven't ever heard anyone say what the 'waste' is from growing hydroponics. There's always something that can't be recycled and must be thrown out, it's kind of like 'conservation of energy' - you always have a little lost that can't be used.

This could easily be the very best way to go but I'd kind of like to know what problems there are yet to solve before I get totally thrilled and forget to ask (yeah, I do that)!