Hi all.... this is the DIY CO2 that I am using. The reason I am posting this is because I think the diffuser is pretty cool. I bought a $15 internal filter at PetSmart. I drilled a hole in the bottom of the foam filter and put my CO2 hose about half way up. When the bubble goes in it gets broken up by the foam, then put through the pump, then finally the TINY bubbles come out the spray bar. I have the unit in the back of my tank under the spray bar for my canister. The bubbles get hit by the water from the canister and they are pushed to the front of the tank. Some of these bubbles then get pushed down the front glass and recirc in thetank.
I don't know how to embed the video... soooo here is a link.
there is a few threads on this but it works well i had dont it with mine for a while. it can handel more bps than i thought i could. i didnt like the spray bar as much as i wanted then co2 to circulate more. nice to share how u did it still.