If your doing the slow release container for your adult shrimps, you can DIY using an upside down clear plastic box (the one that comes with mixed nuts, peanuts, or even some sauces at the supermarket. Use a magnet to hold it against the glass. Now use a screen on the bottom opening, rubber band it in place. The screen needs to have a single little hole in it for the shrimps to swim though. Try panty hose or something similar. This mesh will allow oxygen and waste diffusion.
With the lights on, the shrimps should be on the top half, and when off, they will be evenly distributed. A water current below the box will pull them out of the container though the little hole.
Brine shrimp can live their entire lives in sea water and reproduce, which is way longer then your 2 hour observation.
there is also a simple in tank hatchery available online. air powered.
Do I do this? no, hatching shrimps cause lots and lots of wastes. I hatch them out in 2 L soda bottles, and dump the water out when finished.