Until recently I thought the co2 chart was what it says even if your not injecting co2. But a good friend explained to me that if your not injecting co2 than it doesn't mean anything. Well I am injecting co2 at about 2 bps. So now how does that translate into the chart. Does my ph/kh have to change before the chart is accurate. Is there a test kit for co2 or just that thing you put in your tank and the color changes to not enough, good or too much?