If he is using that hatchery from shrimp direct they are very efficient. I could easily get plenty of bbs a day when i was raising my angel frys - i can't give an exact % but i believe it was extremely high because i kept using less and less eggs (the scoup that comes with it is like 1/8 or 1/16 a teaspoon and i would only fill it 1/4 of the way because that produced plenty for 2 1/2 days after which i needed a fresh batch. It also does a great job of sep shrimp from eggs so you don't have to muck with straining them.How? I mean, I use a bottle hatchery by now, and gave the dish model to a friend, but still: How do you get to that number?