Permanent Co2 Test....

[DoubleJ]

Am I the lucky one that has 5kh tap water??? I have been tinkering with this for a day and a half now and, it seems I get 5kh on the nose every time out of my tap.

 

[JamesC]

There has been a posting on the Barr Report website indicating the way we dry the sodium bicarb is wrong. Heating it above 100 degrees actually breaks it down to sodium carbonate, water and carbon dioxide. Take a look at this link - http/antoine.frostburg.edu/chem/senese/1...mposition.shtml. It seems it would be better to dry the sodium bicarbonate off below 100 degrees but leave it for a lot longer. Think it might need a little more looking into. Could explain the large weight loss that is experienced when heating it up.

James

 

[MoreCoffee]

Thanks James,

I'd not seen the post, but will go and have a look now.

Cheers
Al

 

[MoreCoffee]

I wonder if that has anything to do with the high PH reading I saw and Tom thought that shouldn't be possilbe !

Re Reading this, a pH of 10 should not be possible. Not with baking soda anyway, about a pH of about 8.1-8.3 or so perhaps.

I think you will want to check using a pH meter.That would be better.Neither seems to add up well.

The results I'm seeing do seem to be what I was expecting to see at 30ppm.
Maybe I'll try baking / mixing up another batch when I get some time ..... probably after I've finnished my cycling experiment .... and use a second
drop checker to compare colour reactions between both batches of solution.

I've now got a digital PH probe, so can check the PH with more accuracy.

James: Thanks again for the info

Al

 

[Loyal to the Oil]

Water surface movement is said to help release the CO2 from the water. Therefore if the water movement below the drop checker is faster, surely there will be more CO2 being released into the drop checker, resulting in a false, higher reading? Similarly, if there's less water flow the CO2 released into the drop checker will be less?

The whole idea of CO2 leaving the tank because of surface turbulence is based on diffusion. The reason CO2 wants to leave the tank is because by nature all molecules of any substance tend towards a location of lesser concentration of the molecule (called a concentration gradient) . Since we are adding CO2 to the tank to a concentration of about 30 ppm and the concentration of CO2 in the air is only about 3 ppm and no matter how much CO2 leaves the tank the air will NEVER reach 30 ppm (and become equal to the tank), CO2 will ALWAYS be trying to leave the tank. No matter how still the water in the tank is, CO2 still will be leaving the tank. Turbulence just speeds up this process which is why we try to avoid it.

So now if you think about the drop checker. There is only a small amount of air in that drop checker compared to the air in your room. So the air in the checker will quickly become equalized with the water CO2 concentration (unlike the air in your huge room) and wont go higher than the concentration in the water because the CO2 wants to be equal in concentrations by nature.

So all in all no, the reading will not change based on the turbulence around the drop checker, it will always be as accurate as your original 4 dkH sample. That being said if you think about it, then having turbulence near the drop checker would actually make the checker respond faster to changes of CO2 concentration in the tank because the CO2 will enter or leave the checker faster. But it would be such a small difference you would not notice.

Sorry if this is wordy but i thought i would put in my 2 cents .

James

 

[JamesC]

the concentration of CO2 in the air is only about 3 ppm

The concentration of CO2 in the air is actually between 300 to 600 ppm depending on where in the world you live.
http/en.wikipedia.org/wiki/Carbon_dioxid...on_and_toxicity

James