Ok dude... the white disk is ceramic, and has fine pores... You can pump air through it. Only pressurized CO2 is supposed to pass through it. PRESSURIZED!
An air pump is not pressurized...
DIY CO2 is not anywhere in the realm of being enough pressure for a ceramic diffuser... Sorry to tell you,... wrong buy dude! Best bet is to put it up for sale in the classifieds, and get a powerhead...
BTW a sealed 2 liter bottle with label will withstand 1800 PSI, seriously. If you blow one up with DIY yeast mix, something is really screwy with your mix!
Tyler..some glass diffusers can be used with DIY setups. Here's one of mine. Look closely to the left hand side. You'll see the fine streams of bubbles.

I run three different types of glass diffusers.
However, I have found the nano's don't work. At least the ones I have tested. I have a few more different types coming in to test as well.
As Ghengis said, if the system is leak free...it should be fine. With my nano, I just got paranoid that it would blow, so I pulled it and went back to the regular diffusers that are in the pic.