My DIY CO2 is doing all right, although it does not produce as much as that of some other people I have read about. I currently have two bottles running, changing out one every 10 days. I'm a busy person and don't really enjoy taking the time to change the mixture. But I enjoy making my plants grow well and seeing them pearl.
What I'd like to experiment with now is making a homemade non-electric diffuser. I would like to start doing CO2 on my other tank, but it does not have a power filter, and I wouldn't be interested in buying anything to serve as a diffuser. So I'm going to be experimenting.