add a gas separator between the CO2 generator and the bubble ladder. I use a 20oz soda bottle, 2/3's full of water. run the CO2 into the bottle, and use rigid airline that extends down into the water. Then have a little piece of tubing that vents the CO2 out of the top, and run airline to the bubble ladder.
That should totally eliminate the fluffy, snot-like white stuff, which is indeed some kind of fungal residue from the yeast.