I have read many times about the gooey slime covering an airstone when using yeast DIY CO2 generators. I have experienced that myself. When turning it on, the slime covers the airstone within two days with thick cover.
I think I have read it here that this could be bacteria so that got me thinking that if I can block the bacteria coming from my coke bottle into the tank, that should cure the problem. Well, I have set up another bottle which I filled with concentrated saline water and some potassium permanganate. I put the tube coming from the bottle with yeast mixture into the water of the other bottle. I put another tube from that into the tank. So, now CO2 generated in bottle #1 goes through the solution of bottle #2 and then comes to the aquarium. And guess what. After turning this on, I noticed slight slime presence on the airstone on the second day which then disappeared and by now, several weeks laters, it hasn't come back...
I hope this is useful...
I think I have read it here that this could be bacteria so that got me thinking that if I can block the bacteria coming from my coke bottle into the tank, that should cure the problem. Well, I have set up another bottle which I filled with concentrated saline water and some potassium permanganate. I put the tube coming from the bottle with yeast mixture into the water of the other bottle. I put another tube from that into the tank. So, now CO2 generated in bottle #1 goes through the solution of bottle #2 and then comes to the aquarium. And guess what. After turning this on, I noticed slight slime presence on the airstone on the second day which then disappeared and by now, several weeks laters, it hasn't come back...
I hope this is useful...