1. Attach airline valve to hose and close it. Loop hose over top to prevent backflow.
2. Fill hatchery to within 1 inch of top with brine and artemia eggs.
3. Connect hose to air pump and open valve.
4. If the soda bottles have removable bases, use the second base as a spray shield on top of the hatchery.
To collect nauplii, shut airline valve and disconnect hose from pump. Shine a lamp on the bottom of the hatchery and wait until egg shells have floated and nauplii have gathered at the bottom. Then, move the air hose below water level and open the valve to drain nauplii through a brine shrimp net. Afterwards, close the valve, loop the hose over the top, reconnect to the pump, and open the valve again to resume aeration.
Notes: Water may slowly drip from hole in the cap, but will be caught by the supporting bottle half. You may want to cover the top to reduce salt-spray. Alternately, you may opt to leave the top bottle intact, except for a small hole drilled through its base (although this will complicate cleaning and refilling the hatchery).