Quote: I knew it must be something like that, but it's just not obvious in the pictures, and anyone who doesn't understand how the vacuum principle works might try to build one that LOOKS like yours but omits that critical detail.
It looks good and should work fine
Quote: If you use it outside, it could go next to a fence post and extend into your run and be filled without entering.
To put it against a wall inside, you may need to rotate your ball valves 90 degrees