Don't know about the tub. I'd try it for a month or two with some cheep fish to see if any unexpected problems turn up. Every time I start thinking about cheep tank alternatives I read through the indoor pond sticky, think back to when I made a fountain pool in my backyard out of that black rubber stuff for about 40 bucks, then look at an unused corner of my room. Its a bad, bad train of thought that I prefer to avoid.