I mean depending on how handy you are, and how much of a hack you're willing to deal with, it can be done. I made a hot-tub out of a 12' circular watering trough - the big galvanized things you see on farms. I bought a purpose-built jacuzzi pump/filter, and ran the water through a radiator over my fire pit. It wasn't pretty, but it was cheap and did the job for a number of years. The biggest problem you're going to have is that the *only* thing you're going to re-use is the body/frame, and even then you're going to have problems, because those things aren't meant to hold several hundred pounds of water.