How To Check Co2 Levels By Ph 24 Hr. Ph Water Test?

[amagphoto]

Can't remember how to use the 24 hour water sample to check my Co2 levels.....something pretty simple but just need someone to let me know. Trying to check my CO2 levels to see if using the KH and PH charts give me the same levels....

 

[GoldLenny]

I'm still kind of new to these forums so I'm not sure if this exists out here already but I use this page calculator and chart(s) for CO2 ... http/www.csd.net/~cgadd/aqua/art_plant_co2chart.htm

 

[BHornsey]

I'm still kind of new to these forums so I'm not sure if this exists out here already but I use this page calculator and chart(s) for CO2 ... http/www.csd.net/~cgadd/aqua/art_plant_co2chart.htm

The pH/kH/CO2 relationship tables are OK as a basic check but works only as long as kH/CO2 reactions are the only acids present (Carbonic acid if I remember correctly).
This isn't the case in an average aquarium. There are many forms of acid and all drive down pH. My 30 G tank has a kH of 7 and a pH of about 6.3 which equates to CO2 of about 110ppm! However, this isn't the case. I have a drop checker and it shows a nice healthy 30ppm so obviously pH is being depressed by other acids.

 

[Themuleous]

Can't remember how to use the 24 hour water sample to check my Co2 levels.....something pretty simple but just need someone to let me know. Trying to check my CO2 levels to see if using the KH and PH charts give me the same levels....

Take a sample of the tank water and let it sit for 24/48hrs.

Measure the pH of the that water.

Measure the pH of 'fresh' tank water

Compare the two.

A difference of 1 pH point = 30ppm CO2.

Sam