Definitely keep the air stone on. If you want to grow the shrimp larger, here is how I do it. Use a 5 gallon aquarium or something similar in size...one of the plastic "critter keepers" would work fine. To each gallon of water, mix 10 1/2 ounces of plain salt (no iodide), 2 heaping tbsp of Epsom salt, 1 ounce baking soda, 1/4 tsp active dry yeast. You can add 1/2 tsp of yeast if there are a lot of shrimp in there. Keep water at 78-80 degrees. Have this mixed up and running with an airstone in it for at least 24 hrs before you add shrimp from hatchery. Don't dump hatchery in there...net shrimp in fine net and add them to tank. When water begins to clear, add more yeast. Mix new yeast in fresh water when you feed and try to add about what has evaporated. This will keep salinity about right. Try to keep water slightly cloudy...no need to clean this tank...it gets better with age. They will take about a month to mature. Leave some mature shrimp in there and they will reproduce. This is how I have done it and it works. Fish love them. Shrimp will grow slower if water is colder than 78-80. Keep airstone running at all times.
Logan J