Won't the open grid of the circulation pumps pose a danger to the shrimp?
I would think only for the tiniest babies. With my Korlias, the propeller is pretty small. I would think that it would be at least a 50/50 chance of them not even hitting the propeller. Not sure if the 400 GPH has a bigger propeller, but I would imagine it would. The outside of the pump is the same size, so it should be bigger.