Since your ATO looks like its NOT in a finished living space, what i do is put a tee in the line and run it up to the ceiling attache to wall so it doesn't fall. no ato woll pump up that high when the easiest exit is your ATO resevoiur. As soon as ATO shuts off, the tee line to ceiling breaks siphon. $2.00 investment in a John Guest tee. :)
