Aquatic Plant Forum banner
1 - 4 of 4 Posts

·
Premium Member
Joined
·
7,436 Posts
That chart is not a good way to determine how much CO2 you have in a typical aquarium. The chart is very accurate only if the water has nothing in it that affects the pH or KH except CO2 and carbonates/bicarbonates. A better method is to take a sample of the water in your tank let it sit around long enough to degas the CO2 in it, then measure the pH of that water. Compare this pH to the pH of the tank water a few hours after the CO2 is turned on. The ppm of CO2 you have will be about 3 time 10 raised to the decrease in ph power. For examples: if the pH in the tank is 1.0 lower than in the degassed water, you have 3 x 10, or 30 ppm. If the pH in the tank is 0.8 lower than the degassed water, you have 3 x 10 to the .8 power, or 20 ppm. I will bet that you have less CO2 in the water than you think.
 

·
Premium Member
Joined
·
7,436 Posts
So just before the co2 is switched off I have a ph around 6.5 and next day in the morning, just before the lights turn on I have Ph of 7.0

Does it mean that I have just 15ppm so I should increase CO2 level to go near to 30 ppm?

I realised also that when the kh is 3.5-4 the ph difference is 0.5

However as I am getting close to the water change my kh increase until 6 due to the seiryu stone, then the difference is just 0.2 but I put same co2 in the water...
The CO2 content in the tank, after a night of no Co2, isn't necessarily 3 ppm, but could be 4-5 ppm, which would mean you have a lot more than you think. I like the idea of isolating a cup full of water over night or longer better.
 
1 - 4 of 4 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top