the anti siphon valve is made into the hose barb fitting on the top of your tank, remove the hose barb and look thru it, you will see a check ball, spring and collar. I can't legally tell you what to do with it, But i've float tested them in the past, if it floats in water, its probably good(
), I've taken a Phillips screw drive and punched the check ball, spring and collar out, just to see they were there