No idea on stopping your leak, but I'm curious about your water quality.

Water goes bad when it sits around. It grows bacteria, slime, all sorts of nasty stuff.

In your setup the bottom third of at least one tank never drains. Sounds like a recipe for a fungus amongus.

Do you disinfect anywhere? I wouldn't have any qualms about drinking well water direct from the well, provided there's no local contamination. Water that sits in a storage tank is a different story.