Test Kit Chemicals and Techniques...?

[spinjector]

Hi all,

I think I have asked this before, but I searched for my post and I cannot find it.

I would like to learn about the chemistry behind the cheap little water test kits we all buy at the LFS. I would like to know the chemicals and theory behind some of the common tests we use for things like nitrate, nitrite, ammonia, GH, KH, PH, P, K, and some of the metals like Fe, Mn, Mg, etc.

I have tried to Google for various combinations of keywords like "water testing analysis quality student basics", but I always get *too much* information... I can't find the head or the tail of the beast.

So I was wondering if anyone can help me wade through the weeds to some basic step-by-step information about water tests like I describe above... Things like the reagents and indicator solutions used, and the theory behind the test.

Thanks.

 

[patoloco]

I don't know the exact working of each test, but at a general rule they work by reacting with the specific element.

Most of the test contain elements that change color according a specific situation. Some may work as a stand alone (pH test for example, that changes its color according to the acidity level of the water).

Others, like nitrate test need fro 2 to 4 test reagents to show the test result. These work by preparing and unmasking the element you are looking for, andthe final reagent reacts and produces a color change.

 

[spinjector]

Hmmm sorry perhaps I could have explained this better... What I was looking for was exact descriptions of the chemicals used, and explanations of the expected reactions. For instance, if I walked into a chemistry lab with a water sample, I would need 1 ml of chemical A, two drops of chemical B, and wait for the color change of the indicator solutuion to color X...

Perhaps something that could be described as "Water Analysis for Hydroponics 101"...?