I don't run a skimmer on my tank. I just think it isn't necessary to have a skimmer in a small tank if you can do 1-2 gallon water changes a week and thats already 15%-30%. I have LR and mirco algae in the fuge instead of a skimmer. Oh and, the skimmer also skimms out calcium, salt, and a few good other things. If you use natural ocean water like me, it isn't a good idea if you use a skimmer because it will just skimm out all the good bacteria in the water. Then there wouldn't be any point in buying natural ocean water. But if your tank is heavily stocked, I'd recommend a skimmer.