I love waterfall bongs. I used to use those all the time when I smoked. Got you more ripped than a gravity bong. I used use huge bottles (at least 3L, the kind you get from costco cranberry juice) with widemouths. I'd make it water filtrated by adding a downstem.

Just poke a small hole through the cap. Take like a papermate pen and take out the ink filling. Cut off the closed end. Stick that pen tube through the hole in the cap and you can use something like a thick strong straw to extend it to the bottom. On the top, just stick a metal bowl (with the rubber fitting on the end) onto the other end of the pen tube.

You can then take some foil and fold it over a couple times. Make a bulb that fits around the end of the downstem. Poke some holes with your chick's earring or a push pin, whatever you got, and now you have a downstem with a diffuser. Add your water, and add some ice cubes. You can use duct tape, rubber bands, whatever you got to hold the diffuser and the pen tube to the straw (or whatever you used for the rest of the downstem).

THere, a little modification and you have a water filtrated waterfall bong, with a diffuser, and it's ice cooled. Makes a much better experience, and this really hits straight to the dome. Try it out, :jointsmile::thumbsup: