You could add refugium tank for the shrimp. In my set-up I have 100+ cherry shrimp in a 20 gallon refugium (that are breeding like crazy). Some of the shrimp wander out to the main tanks where they end up being eaten, but the main populus of the shrimp remains intact. Somehow some fry got into the refugium also.
The 20g refugium sits side by side with a 190g tank.
Here's a few pic's of the refugium-

I built a little water-bridge for water to flow through. Only small fish or shrimp can swim through the little water-bridge.
PVC pipe works good for this as well. Just add some end caps to the PVC pipes and drill many holes into the caps so that fish can't swim through it.
This could be done alot nicer than what I have.
I have a video of my set-up in the link in my signature.