Pool heating
If you are thinking about having a pool heater, you need to agree on this BEFORE building the pool.
At least the pre-installation should be done when building the pool; the connection to the heating system can also be implemented later (to save costs now)
As you can see, the nozzles are very long, so you have to dig down about 20cm in front of the foundation so that the nozzles are at the same height as the finished pool floor