It works

I finally swam in solar-panel warmed up water on November 1, at 6 pm, minutes after the installer had left, at a perfect 26 C, or 78.8 F.

We had turned on the system at noon, on a test basis, so not at 100% capacity because our cautious pool guy Alvaro (not the same person as the panel supplier-installer) wants to double check the pressure on the pump and other technical stuff.

When he turned it on, we measured the pool at 20 degrees (68 F), and the water coming into the pool at 23.3 C (74). This low reading at the pool is because although the water from the panels was coming out at about 40 degrees (104F) there was a long stretch of pipes to warm up.

From what I saw during the installation, only a fraction was insulated, and improperly at that, and then there´s the entire length of the filter circulation which is also not insulated. So initially all the pipes and earth surrounding it needs to be warmed up before the water coming out from the panels and the water arriving at the pool have a similar temperature.

All this will eventually be fixed by Alvaro, but right now I don´t feel like engaging in further works, just patching whatever leaks remained, and maybe in February when we have to travel to Asia the rest can be dug out and insulated.