i have recently been experimenting with yeast Co2 injection. using 2 liter pop bottle, underground filter tube (flipped upside down) with a power head forcing a downward current, and a regular airstone. i had an old fine bubble stone but i got this white growth/ooze, and thought it was a mold or something from it being old. i tossed it, went and got a new one. still getting a growth of some kind, but it seems slower now. i havent seen anyone list this as a side effect of the yeast system so wondering what i am doing wrong. i was ganna post a picture, but it wants a http://. it is late and i am lazy so maybe tomorrow. any suggestions are appreciated