Primordial: consult with an architect on Foundation calculation to build the pool box without damaging the house. In your case, you could surely reach some measures for the 6.75 x 2 x 1.10 m glass. A header jet stream It allows swimming without moving. In the background the shower and toilet cabins would be located; in front of them, a sculpture-fountain (the water comes from the treatment plant) and, on the sides, the gymnastics machines. The passage from one side to another would be through a small bridge in the same teak wood of the gym.
It is essential to place a dehumidifier to avoid condensation. The heating would be solved with a heat pump, very fast, and the treatment plant and other engines would be installed in a small garden shed. To purify water, better salt than chlorine, it leaves no smell and is healthier.