I had one on my 55g for about 9 months (tearing that tank down) and didn't really have issues with it, but I also didn't get a lot of skimmate. You do really need to mess with the dial a bit to get the right amount without getting a ton of microbubbles. I didn't have a sump on the 55g either, but if you have a sump on your tank, get an in-sump skimmer, you'll be happy to you did.