Equipment & Supplies • Co2 diffuser

[tmazz71]

I have seen several examples for DIY co2 diffusers (half hemisphere variety) and I was wondering if a glass orb, roughly 4" in diameter with an opening of only about 1" in diameter at the bottom would work or if they need a larger open area at the bottom for more contact between the water and the gas. For reference it's a hummingbird feeder with the stopper pulled from the bottom, I'd post a picture but I'm posting from my phone so I can't until I'm home from work