Where does all the CO2 come from?

[James Findlay]

I am new to this so please forgive any protocol errors.

I am reading consistently high CO2 in two 200 litre tanks which do not have any CO2 injection. Readings are between 25 and 35 ppm according to JBL PROSCAN. I do not add any liquid carbon either.

Plants do OK but they are not a priority in either tanks. One tank has a heavy fish load and the other very light. So where is the CO2 coming from? There is a gas boiler very close to the two tanks. I use Tetra Proline Balance balls in both. Lighting is 68 watts of T5 in both. Does anyone have any idea what might be going on? Oh, nitrate readings are 0 in both tanks as well.

 

[Tommy]

Plants produce co2 as do fish, I don't know if that's the answer though, someone with more knowledge than me will know though.

 

[foxfish]

I would think your readings are not accurate.

 

[oscarlloydjohn]

I have used the JBL proscan, and I think it is quite unreliable. Because the KH measurement on the strip is inaccurate, the calculation for CO2 is also inaccurate. Also any acidifying factors from other sources will show up as a false CO2 reading.

I think the 0 nitrates is also most likely wrong. I've had the same reading and other test kits show nitrate is present.

If the fish aren't showing signs of stress, then it should be fine.

Hope this helps