Maybe not the water changes per say then it must the the quality of our source water. I can tell you one thing though, right after hurricane Ike (remember when I called you) I was w/o electricity for a week & the water quality when down hill. As soon as I got power back, the Clarity went nuts w/ the most amount of foam prodution I've ever seen but a few days later with the normal routine I do, very little foam production.