I'm a CO2 injection newbie, but I would like to start doing so in a new tank that I'm planning. Being new to it, I'm a bit nervous about the whole thing! I've seen this advertised in PFK in the last few issues, and they did a small feature on it in the most recent one. It seems like a good quality, cheap unit for someone wanting to start out with CO2 injection. I just wondered if anyone had used this before or has any comments/advice/whatever in general. Also, is it possible to inject CO2 into a tank with just an internal filter?