Drippers

http://littlegreenhouse.com/accessory/mist2.shtml

these drip stakes look like a very low power way to water plants. they say its for soil but it looks like it could replace the big aquarium motor / pvc tube setup. Instead of pumping water up just hang a res from a shelf and run a tube over the plants watering top down. Anyone tried it?

This one even seems to defy gravity!? (although they say the picture isnt accurate)

Yeah it would work, never tried that type but I've been automatically gravity watering for years, I use a hozelock timer and a res located above the plants. It will have to be drain to waste though or else you will have to use some sort of pump to recycle the run off back to the res.