This is a bulkhead mount float valve. All you need to install it in any tank is to drill a hole in the side wall of the tank. The valve connection stem mounts through the tank wall and you just tighten the back up nut. All of our units have a automatic shut off valves. Add a float valve to your open storage tank and make your system completely automatic. For all of our reefkeepers you need the 1/4 inch float valve. The 3/8 inch is for Merlin and small commercial units. Yes you can operate more than one float valve, in more than one tank. One tank will top off then the next tank will receive water till topped off.