Does anyone know if the gravity 3 ballast system that came with my boat has ballast bags with output, input, & air release? I can't find it anywhere online & unfortunately my boat is not accessible for me to look for myself until spring. I am looking at some second hand bags & the description says there is just the input & an air release. If these are both the case, can a fitting be bought to allow the same input to be used as an output? Can a new output easily be added? Or should I be looking at other bags. The price is really good so that's the reason I was looking in this direction.