Brine shrimps are non-selective filter feeders and can be fed a wide range of foods, including but not limited to Liquidfry brand or similar fry food, yeast, whey, wheat flour, soybean powder, fish meal and egg yolk.
For maximum results, your Brine Shrimp should have food available 24/7. At the same time, you don't want to flood the container with so much food that the shrimp can't consume it all, allowing it to settle to the bottom of the container and starting to decompose. Overfeeding will only add to your container maintenance.
A good "rule of thumb" is to feed just enough of the mixture to make the container water slightly cloudy. Keep an eye on the water and, when it appears to be clear (most or almost all of the food having been consumed), add some more food. Over time, you will know how much and how often to add food to the container.
As you add more and more shrimp to your Grow Out Container (from the daily hatchings) you will need to feed more, more often.
Feeding too much will add to your maintenance woes, while feeding too little will not allow the Brine Shrimp to grow at their optimum rate. It is sort of a "feel" thing, which you will figure out in a short period of time.