Yes, the assumption is correct. It works perfectly however there needs to be a drain valve on the efferent limb of the loop to allow the water to drain from the EZ Green unit. Otherwise, the fertilizer pellets will float to the top and out of the unit or it will create a mess when trying to refill the unit.
My yard is approximately 13000 square feet and I water with well water. I have been using a fertilizer injector called a Turf Mate II. This device is currently on the fritz and I may not be able to find replacement parts. When I installed it I created a loop off of the main line from the well with a back flow valve just in front of the injector. This device mounts to a post near the well and the loop is connected to the main water line by PVC union connectors. In looking at the EZ Green system, ...