How to Read Properly Water Tests Results

Asmack Arabia

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Nov 1, 2012
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Hello,

I bought a few months ago the basic water tests - ph, kh, phosphate, nitrate, and iron. But I am rarely using them, maybe due to laziness or perhaps becuase I am really finding it difficult to tell apart the color ranges of the results. Like for example, I use Elos KH test. It says there, once the solution become yellow, then that is the hardness. But how yellow is yellow? Is it light yellow or should be really yellow, like canary yellow? I know that results should be read in subdued light, ok, I got it but it is the comparison against the charts that I am really struggling with. Can you give me any tips here?

Thank you.
 

dutchy

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That's the trouble with colour based tests. They are subjective to the interpretation of the user and the amount of light present. If you want to be more sure, you should verify the colour to a known solution. Let's say you think you have a KH7 in your tank, you should make a verified KH7 solution and, perform a test with this verified solution and compare the colour with the actual result form the tank. It's the same with the others.

That's really the only way.

The pH test is so crude that it's hardly usable, maybe you can find an electronic pH test better.
 

Asmack Arabia

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oh, is that so? :(
when i bought those tests, i read first a lot of reviews to select the best. i chose salifert for most of them as they have good reviews. but still, its hard to read the colors.
 

dutchy

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For example with NO3, I use a specific amount of KNO3 and add that to 10 liters of water to get a solution that is, for example, 10 ppm NO3. I will use the test on this solution and the colour I get, is sure to be 10 ppm...

It's just that I don't use it because I don't test... :)
 

Asmack Arabia

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Nov 1, 2012
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ohhhhh....me too! i am so lazy to do those tests. (i am not saying you are lazy, its just me... :D)
how i wish there is available digital meter for every water parameter!

but very clever indeed about the verified solutions. since i have seachem N and P and iron, can i use those to make a reference tests?
 

dutchy

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On the bottle it should show the contents. You can recalculate that to how much ml's you have to use on let's say 10 liters to get a verified solution of N, P or Fe.
 

Aviss

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Mar 19, 2012
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Hi,
in KH test it's not important the type of yellow.
When the solution color changes from blue to a color that you identify as yellow then you found your KH.

Regards,
Paolo
 
Last edited by a moderator:

Tom Barr

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Jan 23, 2005
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Left C has a sticky on how to make a reference solution as does Hoppy.

Pretty easy.