That ph2o from the reservoirs runs through the metal tiles, and over time drops down to 23c. From that part of the loop, it then passes into the large cool h2o pool next to the reservoirs. It loops through there in a snake. This ensures that the pool stays ~24c even when we add warmer h2o to that pool.
The pool also has radiant *gas* pipes running through it, therefore ensuring that o2 production is *also* at ~24c.