LaMotte AM-41 Hydroponics Test Kit - Manual (Page 13)

SULFATE
*Sulfate Turb Tablets *6456
The single tablet reduces the pH and precipitates sulfate as barium sulfate
(BaSO
4
). The sulfate level in ppm is determined turbidimetrically.
IRON
*Ferric Iron Test Solution KCNS (thiocyanate) *5116PS
*Iron Reagent Powder Sulfamic Acid *5275
Ferric (Fe +3 ) ions react with the thiocyanate ions in an acid solution to
yield a red or pink color which is ferric thiocyanate.
NITRATE
*Mixed Acid Reagent Acid Salt Solution *V-6278
*Nitrate Reducing Reagent Cadmium Reduction Mixture *V-6279
The Nitrate (NO
3
) is reduced to the Nitrite (NO
2
) by the cadmium
reagent and forms nitrous acid with the salt solution. The nitrous acid
produces a red dyestuff through a diazotization process.
AMMONIA
Ammonia Nitrogen
Reagent #1 Stabilizer-Rochelle Salt
(potassium and sodium
tartrate-APHA Solution) 4797WT
*Ammonia Nitrogen
Reagent #2
Nessler’s Reagent
(anhydrous mercuric iodide,
anhydrous potassium iodide, and
Nessler’s Reagent [anhydrous
mercuric iodide, anhydrous
potassium iodide, and sodium
hydroxide])
*4798WT
Ammonia Reagent #1 is added to prevent precipitation of residual calcium
and magnesium ions in the presence of the alkaline Nessler’s Reagent.
*Ammonia Reagent #2 is then added to the sample. If ammonia is present
a yellow color is developed which is probably oxidimercuric ammonium
iodine (NH
2
Hg
2
0I).
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