Yeah, that's a lot of shrimp. But it does not matter. Almost anything works. Just track the levels, and when ammonia cranks up, pull them out. Yes, programming Apex is a lot easier if you know how to program in general. But hey - this is silicon valley - go learn to program! You have a month to kill waiting for cycle. I notice a lot of threaded PVC fittings. Those tend to leak or crack, so be careful. My preference is to use silicone glue and gently hand tighten. Glue dries for a good seal, but it does not stick to pvc, so still comes apart easily. Glad to see you ditch the brass. I assume that hose clamp is stainless?