Have a frag tank but not sure if you want to tie it in with your display aquarium or run it as a completely separate system? Well, obviously there are advantages and disadvantages to both. If you plumb the frag tank into your main system, you will add volume to the overall setup and won’t have to worry about acclimating livestock if transporting things between tanks. Unfortunately, tying the two setups into one also leaves you open to cross contaminating both tanks with potential parasites, disease, pests and nuisance algae. The big advantage to keeping the two separate is you have a physical barrier protecting livestock. If a disease breaks out in one setup, it won’t affect everything, but is very limited. From an equipment standpoint, obviously adding any amount of volume to an existing setup or as a separate system is going to require additional equipment or upgrading inadequate equipment.