I'm regularly asked about CO2 diffusion, what works best and what would I recommend and the answer is always the same. If you have a CO2 regulator that allows you to adjust your bar pressure to 3 or higher, then Easy Aqua Atomisers are the best. They win hands down every day without fail. And what's more they only cost just over a tenner and are available in small or large varieties.
Not only are these atomiser cheap, but they're also economical in the amount of gas you need. They diffuse CO2 better than any other diffuser I have ever used by creating tiny CO2 bubbles - you actually need less gas when compared to a glass diffuser for example. You see when you're using an Easy Aqua atomiser, the bubbles are so small they literally hang in the water. They don't shoot up to the surface which means it's really easy to push the CO2 around the tank. And the longer the bubbles stay in contact with water, the better the CO2 diffusion and the better your plants will grow. Simple heh :)
Check out the video below to see what I mean.