I used empty soda bottles for the vertical wall unit. Using an old soldering iron, I melted out the holes. Then putting the neck of the bottle through the bottom of the next bottle I then put the cap on (with drain holes in the cap
) until I had a single unit of 4 bottles. They are attached to the wall with small screws. The water is supplied via drip irrigation nozzles from home depot and is tied into the water lines from the pump. Each column cycles about 1 gallon an hour.