I have a white plastic pool tube about 3 feet deep and 5 feet long (used for holding pool toys.) and a green house in the back back partof my backyard noone ever goes back here. I wanna build a cheap hydro system by cheap i mean as cheap as possible im looking for designs all i to want grow is like 4 plants... If someone knows all about this and would like to guide me on this id be more than willing to listen and i have buddys who kinda know about this so they can help also also it doesnt have to be hydro im just looking for a reliable way that is cheap and parts can be bought at hardware stores and plant stores ne help would be awsome thank you