# Salifert CO2 Test Kit Help



## imatrout (May 12, 2005)

I have a Salifert CO2 test kit. The test is a tritation ? test where you count the drops until the color changes from yellow to blue. My question is that the color will change, but not turn completely blue until going through a green stage and a couple of shades of grey. Is this normal? How do you assess the difference between blue/grey and blue or grey/blue? Anybody have experience with this kit?

Thanks!


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## e.lark (May 5, 2005)

I've used similar salifert kits going from pink to blue and there was a purple shade inbetween, I took it to be trivial and that actual blue was the correct reading. You do know that you can just use Chuck's calculator or Co2 chart to get your correct Co2 reading based on KH and PH right?

http://www.csd.net/~cgadd/aqua/art_plant_co2chart.htm


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## imatrout (May 12, 2005)

E.Lark: Yes, I use the CO2 chart regularly, butwas just cross checking CO2 with the test kit. I have a high Kh (16) and a Ph of 8.1 out of the tap that I inject with CO2 down to 7.2


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## e.lark (May 5, 2005)

Right, sorry.. I thought I recognized your name but wasn't sure. Thats a pretty high KH reading. That's off the chart, but it calculates to 30ppm. How do the kit and chart compare?


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## imatrout (May 12, 2005)

E Lark:
That's the funny part. If I keep counting drops until the color passes through a couple of shades of grey and turns distinctly blue, It's right on the mark. My trouble is that some of the shades of grey are kind ok bluish. The instructions just say " count the number of drops until color turns blue" Problem is that "blue" is subjective in this kit as the color gradually changes.


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## e.lark (May 5, 2005)

That's a tough call, maybe someone else could chime in who has experience with this kit but I would say disregard the shades of blue and keep dropping until the blue cannot change any more. Keeping in mind the number of the last drop that made the blue that will not change. ehh... :-s


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## gnatster (Mar 6, 2004)

The CEO of Salifert answers questions in the Salifert forum of Reef Central. May want to pop on there and ask directly.


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