I have a white cloudy substance forming where my CO2 bubbles out into my diy ladder diffuser. I cleaned it off already, but it's coming back. Anyone know what it is? I only have guppies and ottos in my tank along with a lot of plants.

Is this a DIY CO2? Could you be getting some yeast foam into the air line?

Its normal, its airborne contaminents from your DIY CO2.
You need to add a gas separator betwen the DIY chamber and the diffuser.

a 20oz mt. dew bottle works great. Airline from DIY chamber comes in, runs to the bottom. second airline exits the top and goes to the diffuser. Fill halfway with water, so the second airline is NOT submerged. The co2 rises to the top and escapes...the contaminents stay in the water.

no more white snot on the diffuser.

I prefer the 1 liter bottles, bigger cap! just drill holes slightly smaller than your tubings OD , cut at an angle lube and pull it through with a pliers

Wow, thanks for the help everyone. I'll try what you suggested malkore!