The anti siphon valve must be above the pump and the outlet thru-hull if you want it to work. When you get your anti-siphon valve, follow the plumbing instructions on the back of the card and you will have a system that works.
The updated information on this project is that I have found a way to route all the bilge discharge lines to vented loops into the center of the boat. This location will never be below the water line, unless god forbid I am upside down. Regarding the 2" vented loop I decided to make one myself by joining together 2 90 degree fiberglassexhaust elbows.