I have had good luck with my ghost shrimp. I do not use brackish water (salinity is 0.2ppt) and have produced about 50 living shrimp from about 17 original bought shrimp (over 6 months). The problem with ghost shrimp is that they are treated as feeders so the living conditions in the stores are not the best. Out of the 17 I started with about 2/3 died. But I was able to find a way to keep the fry alive.
I have had tall fast growing stem plants in the tanks with them. I let the plants get to the surface and once the eggs hatch the fry will float to the top of the water and "hide" in the leaves. For feeding I use ground up Spirulina Algae. The plant that they seemed to hide in the most was Cabomba.
The gestation period is about 30 days. The eggs will turn from green (they show up in the saddle first, and then move to the abdomen once fertilized) to clear / whitish and toward the end before they hatch you can start to see little black dots in the eggs.