Well, mine's been up and running now for about four days. The first two days, I could barely turn the water level up without it overflowing. It was also not producing any sort of foam. I ended up cutting the tubing in the bubble diffuser a couple of inches. After that, I was getting tons of microbubbles for a day. They have since gone away and as of yesterday, I am getting skimmate. I was a little disappointed at first, but I guess it just needed a little tweaking and as it says, to "break-in."