Hi Paolo,
Thanks so much for your quick reply. Your attachment is spot on. Both water tanks are already within wifi range of each other (and more importantly the router). I can absolutely install sensor 1 in top of tank 1 and 2. I am not sure as to whether to use an electronic sensor for tank 2 or a manual float valve to stop the well pump from filling it at this stage as either should work fine. If you could assist with the schematics and component list and SW would be awesome.
Thanks again,
Raoul