I'm using 2 tanks:
First tank with medicine to take care all common diease like ick, whiteaspot...etc that commonly come from feeders, this is bare tank with filter that cirle the water.
The second tank same size that after I quarantined my live stock atleast a week then I move them to this tank, this tank I setup with undergravel filter and a biowheel filter and some plants. I always feed my live stock full then use them to feed my monster that's way my monster will get some nutrition from those flake/pellets that my feeder ate few nims ago.
Edit: both tanks are 20 galons