By hatching them in a container in the main tank you save the expense of another heater. The lid stops the salt water from getting into the main tank. When I want to use them, I remove the jar from the tank and sit it on the table with a lamp overhead then wait a few minutes for the stuff to settle and the naupli to head towards the light (makes it sound like they get a near death experience. I wonder if they see their long dead relatives?) Of course, when they are then sucked out with the turkey baster, it is an actual death experience :gigl:
To feed them out, I sit a clean hankie over the jar then squirt the naupli into the hankie so the water goes back into the jar. I then give them a quick rinse under the tap (although not sure if this is really necessary) and dip the hankie into the tank to feed.