I'm pretty sure this is from the yeast mixture that got into the tank. I'm using the Hagen bubble ladder and noticed white slim near the end of the tube and tried to remove it. A few pieces broke away and this is the result two days later. It is starting to cover every thing in the tank. I just performed a 50% water change, hopefully the chlorine kill off the yeast cells. I'm hoping due to the lack of sugar in the water that the yeast will also starve.