Renovating house and deciding about putting in a swim spa/current pool (small pool where you swim against a current). Anyone have one? I wonder how much they cost. We live in southern NH and am also debating whether to have it outside (can't use in long winter but cheaper than building addition) or put one inside a house addition (more expensive but usable year-round). An option is to site it outdoors and erect some kind of greenhouse over it that can be heated, by solar if nothing else, to extend swimming season. I would love the current pool to not look plasticky but like a real pool with stone terrace around it. I've read that manufactured swim spas don't always last so long and that a custom built one is better (but more expensive I'm sure). What kind of maintenance is needed? Thanks!