awesome that answers alot. but im still confused on something, i hope u guys can help with this. but how does the water from inside the bucket get delivered to the halo, or the surface, with just an AIR pump?

i want to build one just like the DWC sticky (http://boards.cannabis.com/grow-log/...-dwc-grow.html). but i dont know how the water will get delivered to the top with an air pump and not a water pump thanks guys.