I have little funds at this time, have seen hot tubs for free on craigslist. I'm thinking 300 + gallons pumps and the heaters if they can go low enough and its free, this could be something hmmm. This may be a start. The tanks would be strong the flow of the pumps should move water to keep it clean and it looks OK. Does anybody have in put on this idea?
I don't know about the free hot tubs. But you can try the denver hot tubz. These hot tubs dealer not only makes the new model of hot tub as we want but also repairs the hot tubs. The Everything Hot tubz dealers also has the best ingredients added in the hot tub which has best soothing and effect that is required for our body.
People have used hot tubs as FT with success. I'd cover it over so the fish can't jump out though. I wonder what the cost would be to operate it vs an aquaponics setup. If you try it, please keep us posted. You can also do a search on this site home page at the upper right "hot tubs as fish tanks".