Detail of the components of the garden hose fill/vent (top).
The gravity fill is also pictured.
Final freshwater fill aparatus.
Water fill test before enclosing the box.
Next we added 2" x 4" vertical supports/tank braces, and fastened the frame to the floor with 2" x 4" straps.
Next we covered half of the top with 3/4" plywood.
At the head, where the water fills are located, we cut out a panel to serve as an access hatch. Leftover piano hinge secures the far side, and a 1.25" hole provides a handle.
The rest of the top is covered, and the access hatch is opened.
Available storage space -- 16" high, 72" long, and 22" deep. We will find a way to keep a portion of the tank visible for monitoring the water level.
Final bed/storage/water tank frame.