Does it work? ADA glass dropcheck co2 indicator - Page 8 - General Aquarium Plants Discussions

Nevermore · 11-09-2008, 04:55 PM

Quote:

Originally Posted by Manwithnofish

Correct me if I'm wrong (like that won't happen)...but why is the selection of kH=4 critical?

Would a kH=6.0 as your standard work? As long as you KNOW what the standard value of your solution is, wouldn't it work? Or does the color range ONLY work when the kH=4.0?

It works best with kH=4. People do use other values. Here is a very good article that explains it: http://www.barrreport.com/articles/2...s-why-how.html

HTH

jmontee · 11-09-2008, 04:55 PM

The reason that 4dkH water is necessary is because it has to do with an equilibrium. Deionized water that has bicarbonate added to it to a concentration of 4dKH is pH 6.6 when it has 30ppm CO2 dissolved in it. This is what makes the solution turn green. As the CO2 changes the pH changes so the color of the solution changes. If you use a 6dkH solution thyen the equilibrium point changes and a pH of 6.6 would need a lot more CO2. If you use a 6dKH soluton and push enough CO2 to make it green then you would have 45ppm CO2 which is just toxic for fish.

Nevermore · 11-09-2008, 05:30 PM

Quote:

Originally Posted by jmontee

The reason that 4dkH water is necessary is because it has to do with an equilibrium. Deionized water that has bicarbonate added to it to a concentration of 4dKH is pH 6.6 when it has 30ppm CO2 dissolved in it. This is what makes the solution turn green. As the CO2 changes the pH changes so the color of the solution changes. If you use a 6dkH solution thyen the equilibrium point changes and a pH of 6.6 would need a lot more CO2. If you use a 6dKH soluton and push enough CO2 to make it green then you would have 45ppm CO2 which is just toxic for fish.

I'm still understanding it myself. That explanation is very helpful. I'm aware that 5dkH standards are sold.

Manwithnofish · 11-09-2008, 06:28 PM

Quote:

Originally Posted by jmontee

The reason that 4dkH water is necessary is because it has to do with an equilibrium. Deionized water that has bicarbonate added to it to a concentration of 4dKH is pH 6.6 when it has 30ppm CO2 dissolved in it. This is what makes the solution turn green. As the CO2 changes the pH changes so the color of the solution changes. If you use a 6dkH solution thyen the equilibrium point changes and a pH of 6.6 would need a lot more CO2. If you use a 6dKH soluton and push enough CO2 to make it green then you would have 45ppm CO2 which is just toxic for fish.

That's hitting the nail on the head for me. Thanks.

Nevermore · 11-24-2008, 07:14 PM

I have ADA's drop checker. Instead of filling the checker with aquarium water as they direct, can I fill it with 4 dKH soln and use their pH indicator soln? Or is there something else in their pH indicator soln besides bromothymol blue that will make that not work?