In this setup, the traditional sump or refuguim has been eleveted to display tank status. the novel approach has lately been gaining a lot of support, as it should.
The real difference between a traditional reef tank and its sump is in the nature, or rather the size, of its livestock inhabits. in a very real sense, it is a predator-pray distinction, with predators mostly in th display and prey mostly in the sump. in order to get the benefits of having both, it is necessary to keep them largely separate, since within the confines of a single aquarium it is imossible to maitain populations of the prey organisms sufficiently high that the predators will not completely wipe them out.
These prey organisms, however, are extremely important to the stable miniecosystem you are trying to acheive. Therefore by devoting a seperate aquarium to the cultivation of these animals, and by permitting a small but constant flow of them into the other tank, you can literally have the best of both worlds-----by having both worlds
another way in which the sump has been eleveted in this system is that while a sump is traditionally under the main tank , in this setup it shoud be located either level with or above level of the fish-and-invertebrate tank. the reason for this is planktons.