# Nutrafin test kit gh/kh questions



## duckdog (Oct 21, 2005)

I want to make sure I am doing this right I just noticed that I may not have been as per directions (brief)

1. Take a sample of water 5ml
2. add 1 drop of gh or kh reagen depending on test a pink colour should appear for gh and a blue color for kh
3. Continue to add one drop at a time and shake counting each drop until color changes
4. multiply the number of drops x 20 to get gh with gh test and multiply number of drops by ten when doing the kh

Ok here are the questions? 

1. Do i count the first drop added I am assuming no
2 To get a dh reading I multiply my gh or kh by .056 according to the chart 

doing as stated and not counting the first drop on the test

gh 9 drops x 20 = gh of 180 x 0.56 = 10.08 dh
kh 9 drops x 10 = kh of 90 x 0.56 = 5.04 dh

are my calculations correct?

Thank you
Nelson


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## fish7days (Jul 30, 2005)

I have the same kit. Your method looks fine to me. Don't count the first drop and multiply by 0.056 or divide by 17.85.

André


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## duckdog (Oct 21, 2005)

Thank you fih7days now I guess I need to lower my gh lol


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## Edward (May 25, 2004)

Hagen Nutrafin.
Simply, 1 drop GH kit = 1 dGH and 1 drop KH kit = 0.5 dKH, in 10 ml.

Edward


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## Left C (Jun 14, 2005)

duckdog said:


> *1. Do i count the first drop added I am assuming no*
> 2 To get a dh reading I multiply my gh or kh by .056 according to the chart
> 
> doing as stated and not counting the first drop on the test
> ...


Be sure and count the first drop.

Your calculations are correct.

Also, to convert German degrees of KH or GH, divide by 17.86 to get ppm.

If you get AP's KH kit, the number of drops equals the number of degrees. It's easy to use. But, AP's GH kit is too hard to read. It goes from greenish yellow to yellowish green. It's too tough to call where the color change occurs.


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## Salt (Apr 5, 2005)

I don't have any experience with the Nutrifin kit. In order to know what your actual readings are, you have to know what equivalent the kit is testing for.

Dividing by 17.86 is only correct if the test kit gives readings in Calcium Carbonate (CaCO3) equivalent. So if the final kH reading (number of drops x 10) is a CaCO3 equivalent, then yes, dividing by 17.86 will yield degrees of alkaline hardness. (One degree of alkaline hardness is equal to 17.86 ppm of CaCO3, which contains 7.15 ppm of calcium and 10.71 ppm of carbonate.)

The same applies to general hardness. If the test kit reads in the equivalent of CaCO3, then dividing by 17.86 will also yield degrees of general hardness. However, if the test kit reads in the equivalent of Calcium Oxide (CaO), then you would divide by 10 to get degrees of general hardness. (One degree of general hardness is equal to 10 ppm of Calcium Oxide, which contains 7.15 ppm of calcium and 2.85 ppm of oxygen.)

(The term "general" is sort of a misnomer... it's "total hardness." The German word for carbonate is _karbonat_, hence "KH". The German word for total is _gesamtmenge_, hence "GH". Rather than making up a new term for English speakers - "TH" - it's instead thought of as "German Hardness" or "General Hardness.")

To sum up... you need to know what chemical equivalence your test kit is measuring!


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