wht kind of skimmer did you buy? A HOB skimmer is really all you need for that size tank. If you get a you will need some type of overflow to get the water from display tank to sump and a return pump to return the clean water back to the display tank. And if you do that you should have more than one chamber in the sump. You will want to separate your skimmer section from your return section. Easier to do a hang on type skimmer.