Do a google search for DIY sump and you'll find a ton of info on not only how to build a sump, but also the benefits. IMHO a 10 gallon is a bit small and won't alow for much extra volume for when your pump stop (power goes out). Some of the immediate benefits I can think of is that you can put all of your additional equipment (heater, skimmer, any reactors, etc..) into the sump so it will clean up your display. If you have a refugium along with the sump you can add even more benefits. Sumps are not hard to make, the best advice I got when I got a sump was to make it as large as my stand would allow.