If you can get your hands on an auto shut off it should come with instructions but basically it has two fittings on one side and four on the other. The two side is for feed water (unfiltered water) and back out to the membrane. Then on the other side one fitting will take filtered water out of the membrane, one to the drain, one to the faucet and one to the storage tank. As far as the float you can use standard 1/4 inch fittings, mine is threaded and takes a 1/4 inch compression fitting with a nut, a ferrule (the thing that goes around the tubing and holds it in place) and insert ( the thing that goes in the tubing to keep the nut from crushing it. I will look into where to get auto shut offs, although I might be willing to part with one I have just to see a little less water get wasted. As far as what comes out of this auto shut off ( which usually has a flow control incorporated in it) it is waste water, or bad stuff taken from the membrane. Unfortunately when the storage tank is full the drain water just runs straight through to this drain on the membrane and goes down your drain. Flow Control def: a flow control, which you have whether you hve an auto shut off or not just regulates the water going through, basically creating enough pressure to fill the storage tank which is also pressurized. Does that help?