You say sealed... just a comment from my setup in the Campervan ... I have a pair of 25L containers which have the main filler neck into which I have a pipe sealed onto the cap and a small little red cap on the opposite side. I find I have to undo the little cap a bit to allow air to come in - replacing the water drawn. If I forget to open that, the increased pressure on warmer days does make the containers bulge a bit and when drawing water they collapse in and the water seems to slow. With a strong tank like yours that won't give, a sealed system would make the pump work harder and harder and soon could not pull water out? Surely you will need a vented tank to avoid that?Gonna have to get my head round that.......as its sealed the pressure wont change inside and suspect tank strength should mean pressure drop outside shouldn't be a problem. Definitely to mull it over though.
Sensors, hah, not a chance!!! Permanent marker is as techy as it will get
I've spent the afternoon considering your valid points;My concern was 1. Condensation. 2. Warm water is not so nice to drink.