I'm currently doing my first hydro, its a constant drip system using a 35gal rubbermaid rez. I like it alot, the plants are growing strong as hell. using the tub is a great idea IMO. i flooded my floor once due to a faulty hose, so being in a tub would solve that. a lot of people say that DWC is the easiest way to get into hydro, you might want to look that way. my biggest issue is with overcrowding, i wish my plants were in containers so i could space them out and move them around more.

it sounds to me like you've got plenty of lights so thats good. i wouldn't think you'll have to spend too much money, i'd bet you can get some containors and hydroton, pumps, hosing, and ph up/down for $100.

good luck