This is a simple brine shrimp hatchery base for culturing brine shrimp for fish breeders.Print it out and screw on a plastic 2 liter bottle with it's base cut off (see photo at left). Once printed, I suggest brushing the inside with acetone to make it water tight. Optionally, add a rubber o-ring at the bottom of the threads to help seal it even more. Attach the airline from your air pump to the nipple protruding vertically from the hatchery base.Make sure to use an airline check valve in case of a power outage as one does not want the water in this hatchery to back flow into the air pump.Requires "2LscrewPositive.11.stl" from "2 Liter bottle threads" found at: http://www.thingiverse.com/thing:10489Place this file in the same directory as the scad file from this thing if you wish to modify it.I'd recommend printing this at a high percent infill and with 2 shells in order to waterproof it further. Coating the inside with acetone or an ABS/acetone mix helps too.The o-ring that I ended up using was a simple red-brown o-ring used for sealing the connections for garden hoses. I bought a 10-pack for $1.37 at my local hardware store.For information on how to culture brine shrimp, please see the following articles:The Breeder's Net: Artemia Nauplii As A Food Source By Frank Marini, Ph.D. http://www.advancedaquarist.com/2002/12/breederIf you are interested in breeding marine fish, I highly suggest checking out the Marine Breeding Initiative at http://mbisite.org/Enjoy!