Way back when I used a Tunze 230, I think, which sat on top of the tank. It did a really good job but it was a little noisy, it made a whistling sound when it sucked in the air. Overall they're better skimmer than the Octopus line, but they do cost a lot more. A lot of skimmer produce foam right out of the box, even Sea Clones, and a lot of that is due to oil or material inside the new skimmer, so you probably need to give it some time and see if it actually works better.