I went from using straight excel to a combination of the two after I built a DIY system. Plants haven't been better. Making the system was honestly very easy after I ordered silicone tubing, and some suction cups off ebay it took me no more than half an hour. Getting the yeast dosing was tricky, but I always add a bit more because yeast is cheap, and having a slight excess of co2 is not a big deal. With that said, you may get algae issues depending on your lighting and maintenance as I get some slight buildup around the submersed tubing and diffuser. Another problem I still currently have is getting a diffuser that will work. Glass diffusers need more stable pressure than what most DIY systems can produce, and I'm currently using the chopstick method. This works fine, but I'm still trying to find a better alternative. Good luck!