[lcstorc]

ATO can be made from most any container.
The difference between separating the fuge or not is water flow. You generally want much slower flow in the fuge than in the sump. Many people do however have combos and they are certainly helpful.
I've never had a closed looo so I am lost on that one. I should be setting up a manifold systsem soon so we will see how that works out.