Problem testing CO2

[saturday]

I just got the Red Sea plant test kit with FE and CO2 tests. My CO2 test comes out with the 1st drop as already the "overdose" color, meaning i suppose that my CO2 is less than 2ppm. I bought some flouish excel and did the beginners dose and two days later the daily dose and tested again with the same readings. However I was looking at old forum threads and found "chucks plant calculator" and according to that, my CO2 should be at 12ppm. My plants are alive and growing at an ok rate, not superfast but pretty good. My ph is 7.0, KH is 4 degrees, ammonia and nitrite 0, nitrate 5ppm and according to the Red Sea test Fe 0.2ppm and CO2 less than 2ppm. So what do you think my real co2 level is? Is is super low (and I need to fix it) or ok?

[Harlock]

A lot of CO2 and iron tests are not too accurate. I think you are much better off testing KH and pH and figuring out your CO2.

[saturday]

Thanks, I guess I won't worry about it then. Do you think Flourish Excel is helpful or should I not need it?

[Harlock]

Thanks, I guess I won't worry about it then. Do you think Flourish Excel is helpful or should I not need it?
I use it. So, I won't claim it is necessary, but I will say it's made my tank look pretty nice.

[RTR]

Seachem's Excel will not register as CO2 on the charts for KH/pH supression readings of CO2, because it is not CO2, but an alternative bioavailable carbon source.

BTW, I use Excel also.