I'm back, I wanted to add more to this. Here's some additional comments:
1. Q:What is an Eclipse system, anyway?. A:It's basically a Power Filter, Wet/Dry filter, and Power Head built into one unit (the top that covers the aquarium).
2. Q:What is the difference between getting an Eclipse system and setting up all the above items separately? A: There IS no difference!
There is absolutely NO DIFFERENCE from setting up an Octopus tank with a CANNISTER FILTER or an ECLIPSE SYSTEM. Bio-wheels, Bio balls, Bio towers, they're all the same!
In fact, one could argue that an Eclipse system is BETTER than a cannister filter, because:
A) Bioballs and and the like type of filter media in CANNISTER FILTERS tend to trap detritus and you can't see it when this happens.
B) CANNISTER FILTERS are harder to maintain properly. You have to turn them off, open them up, and be careful about the seals in order to service them. Also, IF A SMALL BLOCKAGE OCCURS, YOU WILL NOT KNOW ABOUT IT UNTIL YOU SERVICE THE UNIT.
C) The Bio-wheel is exposed to much more oxygen and constant wet/dry states compared to a CANNISTER FILTER's bio-tubes/balls/etc, which are always submerged inside the cannister.
An Eclipse system is not optimal for growing corals and true mini reef tanks, because the LIGHTING is not strong enough for growing corals, not because it can't handle the load!
For a FISH ONLY W/ LIVE ROCK tank, or an OCTOPUS W/LIVE ROCK tank, an Eclipse system will work fine as long as you include a protein skimmer in that equation.
Again, I'm talking about BIOLOGICAL FILTRATION when speaking of the bio-wheel and live rock in the previous posts above, NOT CHEMICAL/MECHANICAL which is provided by the carbon and pre-filter pad in both the cannister and Eclipse systems.
Obviously if you had a tank with just live rock and no other filtration method, especially in such a small system, the tank inhabitants would quickly succumb!