Newly hatched brine shrimp are very small. Take the airstone out of the container and situate a light source to one side of the hatching container. After a few minutes you should see a mass of very small pinkish red pinpoints collected near the light. They are so very small they are easy to miss if you have never hatched them out before. This is just a guess, that they are hatching and you're not able to see them. HTH.