I have diy co2 system for my 29g tank.

Heres a bit of story...
Last week, I noticed that the co2 misting has decreased. Naturally I thought that one of the bottle was "dead" so I whipped up a new bottle. I should have checked the bottles before I whipped up new one... the bottles currently in use was just fine. I went ahead and swapped out one of the bottle though.

I decided to check for leak or blockages. No leaks...

Then I decided to check the airline running into the powerhead/sponge filter. I was surprised at what I found. I found this milky white thick substance completelly covered the end of airline. As I pulled the airline out of the filter, the substance came off and I heard a quite loud 'SSSSSSSSS' sound.

I actually put the substance and a piece of airline in a ziplock and put it in fridge as I wanted to look at it under microscope at school, but never gotten around to it yet.

So what is this substance? Is it a microorganism that likes co2?
How do I prevent this from happening again?

Sorry if this is a bit of read for some of you

DIY produces more than just CO2. It produces alcohol and alcohol vapor, and it produces organic gunk, sometimes called yeast snot. That is what you found in the air line. If you run the CO2 thru a bubble counter the gunk is stopped by the water and mostly CO2 goes on to the tank. But, it will not be pure CO2 in any case. One more reason why pressurized CO2 is better.

I'm aware that DIY co2 produces more than just CO2. I just wanted to find out if that gunk creating blockage is a type of microorgansim or just some plain "gunk"
I actually have been looking into getting pressurized system. I can't get one just yet.... not until I've done my xmas shopping first

Thanks for your comment Vaughn