Okies, well it seems to work well enough - my guess is it would also work well with DIY CO2 as it needs little pressure to push CO2 bubbles into the filter tubing. I get a steady mist of tiny bubbles into the aquarium even at a massively low 1bpm. I admit to having no drop checker on the tank (naughty me) as I tend to just crank CO2 up until the fish complain, then knock it down a little - on my old setup I always needed at least 30bpm (using the same bubble counter from my old setup) to reach a green drop checker but as yet I don't know how well this Boyu setup with mist around the aquarium will behave. I'm going to order another drop checker (broke my last one) so I can get a bpm count before putting it away again - less is more for me, can't do all this measuring stuff any more! Linky: http://cgi.ebay.co.uk/CO2-Carbon-Dioxid ... 7C294%3A50 All of Â£4.98 delivered too, can't argue with that!