Drop Checker reading and CO2

[Jaap]

Hi,

I have a drop checker question for you.

Case 1: I add 20ppm CO2 in 20 degrees Celsius water where 15ppm stay in and 5ppm are dissipated.
Case 2: I add 20ppm but in 30 degrees Celsius water and I assume more is dissipated so 10ppm stays in water and 10 ppm is dissipated.

In case 1 does the DC show the 5ppm that is dissipated and in case 2 the 10ppm that is dissipated? How does this work?


Thanks

 

[Jose]

In case 1 does the DC show the 5ppm that is dissipated and in case 2 the 10ppm that is dissipated?

No. Drop checkers measure what is in the water. So if it has "dissipated" its not in the water so drop checker does not pick it up. As long as enough time has passed for the DC to be in equilibrium with the water of course.

 

[xim]

The function of a DC unit relies on CO2 transfer between two liquids (tank water and DC's solution) separated by an air gap. The process will result in the same CO2 level in those two liquids.

When you inject CO2, the CO2 in the tank water rises above the equilibrium with the air, and it will escape. Some will escape into the Earth's atmosphere, some will escape into the small air gap at the DC's mouth. Since the air gap is very small, the CO2 level there will be much higher than the atmosphere and it will transfer/bleed into the DC's solution. Eventually, the CO2 level in the DC's solution will be the same as in the tank water.

When you stop CO2 injection, the CO2 level in the tank water drops. Now the CO2 level in the DC's air gap is not in equilibrium with the tank water. It will bleed into the tank water and the CO2 in the solution will escape into the air gap. In short, the direction of the process is now reversed. Eventually, the CO2 level in the solution will be the same as in the tank water.

 

[Andy Thurston]

 

[xim]

A DC is a close unit. CO2 that dissipated into the DC has no way to go unlike that dissipated into the atmosphere.
It will accumulate there and eventually the CO2 level in the DC solution will be the same as in the tank water.

 

[Andy Thurston]

I know what and how a dc works

is how i feel about the op question

 

[dw1305]

Hi all,

The function of a DC unit relies on CO2 transfer between two liquids (tank water and DC's solution) separated by an air gap. The process will result in the same CO2 level in those two liquids.

When you inject CO2, the CO2 in the tank water rises above the equilibrium with the air, and it will escape. Some will escape into the Earth's atmosphere, some will escape into the small air gap at the DC's mouth. Since the air gap is very small, the CO2 level there will be much higher than the atmosphere and it will transfer/bleed into the DC's solution. Eventually, the CO2 level in the DC's solution will be the same as in the tank water.

When you stop CO2 injection, the CO2 level in the tank water drops. Now the CO2 level in the DC's air gap is not in equilibrium with the tank water. It will bleed into the tank water and the CO2 in the solution will escape into the air gap. In short, the direction of the process is now reversed. Eventually, the CO2 level in the solution will be the same as in the tank water.

That one.

cheers Darrel