Go to the setup and filtration and the DIY projects and ideas, look around for a couple hours to get a general idea of what you want to do, and then post what you think you want to do in the DIY section. Very basically, a sump is just a tank which you drain water to from your tank that has a section which houses hgh surface area biomedia, generally placed under a trickle of water so that it is exposed to a lot of oxygen, and a large sump area where you can put thing like heaters, UV sterilizers, protein skimmers, etc. Then the water is pumped back to your tank. That is a very cursory explaination of course, but look at the sections references above and you will find better info. The hardest part I think for you is going to be all the plumbing - a central system like that is going to require lots of PVC running from each tank to the sump and vice versa - to me thats ahrder than building the actual sump, but see what other people have to say in the DIY section about that.
