Red Sea CO2 indicator

mathman

Guru Class Expert
Mar 8, 2011
260
1
18
California
Hi,

I have a red sea co2 indicator whose instructions state to use aquarium water and a couple of drops from the provided solution. However, I read in some post that the co2 measurement is inaccurate when used with aquarium water. Instead they suggest to use a 4kh solution. Is their a way I can make this myself? If so, please explain what I need thank you.
 
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mathman

Guru Class Expert
Mar 8, 2011
260
1
18
California
Hi dutchy,

The link you provided states, "Now take the Measuring cylinder and fill up to the 450ml mark with Demin/RO and transfer to a 500ml sample jar, next add 50ml of the 40dKH to the same sample jar."

The step before this explains that one should mix 1000ml of RO water with 1.2 grams of sodium bicarbonate. If we are using only 50ml of this solution to the 500ml cylinder...what happens with the rest? Can it be used for later?
 
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mathman

Guru Class Expert
Mar 8, 2011
260
1
18
California
Two questions...

Is demin RO water the same as distilled water?

Will this DIY solution change colors (blue, green, and yellow) with respect to the co2 levels in the tank?

Thank you.
 

dutchy

Plant Guru Team
Lifetime Member
Jul 6, 2009
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I think full RO is the same as distilled... (correct me if I'm wrong)

Some evaporated water will enter the test. The colour changes because the pH changes. It's basically not more than a pH test.
 

mathman

Guru Class Expert
Mar 8, 2011
260
1
18
California
The addition of sodium bicarbonate will increase not only the KH level but also the pH of the RO water...is the pH increase unimportant as long as the solution comes out to be 4dKH?
 

pat w

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Nov 4, 2009
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dutchy;74859 said:
I think full RO is the same as distilled... (correct me if I'm wrong)

Some evaporated water will enter the test. The colour changes because the pH changes. It's basically not more than a pH test.

Distilled is condensed water vapor and as such could contain lingering volatile components. RO is reverse osmosis. Water is passed through a RO membrane to remove contaminants and will produce a purer result. DI (de-Ionized) takes it one step further by passing the effluent of the RO product through a de-ionoizing resin bed. DI is about as pure H2O as you can get as far as I know.

In any event either distilled or RO is fine for making a DC solution. Just make sure the baking soda is very dry before you weigh it. Oven dry at 125 F for about an hour will do. Don't get it too hot or it will become sodium carbonate instead of BI-carbonate and the recipe is no longer valid.