I was curoius as to the get what you pay for concerning skimmers. To me they looked like a simple water and air mixer and nothing more. I've never had one so i couldn't tell a ferrari from a yugo when comes to them so thank you all for the advice. I don't have a sump, but is a sump no more than an extra tank with a water inlet and outlet and what are the benefits to having one besides increased water volume. I only ask because i say i'll only have a few things(fish, corals, etc.) but will wind up with a long list of life to look after. So if a sump is beneficial, i'd sure like to know why