Breeding brine shrimp

I have been breeding brine shrimp for two weeks i have been feeding them a product called green water. I have them in a 5 gallon tank but I hatched them in the tank now I have shells on the bottom. But I have some adults and some shrimp with what look like eggs attacked to them. I noticed today that there where some dead ones floating in my little breeder tank. Why is this? Also how do water changes work? I use water from my tank for the shrimp. Also how big do brine shrimp get?