[Myka]

The Octopus and the SeaClone (in particular) are a complete waste of money. The Super Skimmer is likely to give you a wet floor, but is an ok skimmer otherwise. Honestly, make enough room in the sump for an in sump skimmer, and buy a Vertex or used EuroReef. Don't skimp on a skimmer, for a novice reef keeper, a good skimmer will buffer some of your mistakes and save your butt.

I would say toss the sponge...it will become a nitrate factory. Any media you put in the tank you want to remove in a short period of time because it will collect detritus and allow it to break down causing a rise in nitrates. Thus the point of a good protein skimmer...to remove the organic impurities before they can break down. Use some filter floss/padding instead, and plan to replace it twice a week - replace not rinse. J&L sells 18x36" rolls of it for $4 which you can cut to size. What are those colored "water conditioning" medias?

When building a sump like you are planning you need the water to overflow back into the tank, and be sucked into the sump to keep a consistent water level in the display part of the tank. If you push out of the sump with your design you will end up overflowing your tank at some point no doubt. Also, I wouldn't put sand in the sump as there will be too much flow in there it will siwrl around too much, and there really is no point with your design.