[comanswoodwork]

I have briefly looked at a working sump system at a friends shop and think it looks like a good idea but I have a few questions. First would be what kind of pumps are you using and where are you getting them? Does the water that is being filtered only come from the top of the tank? If so wouldnt it be better if you were also filtering water from the bottom of the tank to collect particles that are settling in the tank? Im not entirely sure of the whole design principles.

 

[pistolpete]

The water has to come from the top of the tank because it is an overflow principle. If you were drawing from the bottom of the tank the whole thing would drain out. There is a way to draw water from the bottom with a double baffle system, but it really isn't necessary.
Little giant is a brand that I like because they are built like a tank, but there are many others. A good place to start looking is on line and then at your local fish store.