LaMotte AG-103 Fresh Water Aquarium - Manual (Page 5)

PRO CE DURE
1.
Fill a test tube (0843) to the 10 mL line with sample water.
2. Add 8 drops of Ammonia Nitrogen Reagent #1 (4797WT). Cap and
swirl to mix. Wait one minute before proceeding to next step.
NOTE:
When testing salt (sea) water, increase the amount of this
reagent to 20 drops to avoid a precipitate which may form.
3. Use pipet (0354) to add 1 mL of Ammonia Nitrogen Reagent #2
(4798PS). Cap and mix. Wait five minutes for color development.
Remove cap.
4. Remove cap and insert tube into the Axial Reader Comparator (2071).
Follow the Axial Reader instructions to compare the sample color with
the color standards. Record result as ppm Ammonia-Nitrogen (NH
3
-N).
To express results as Unionized Ammonia (NH
3
):
Unionized Ammonia (NH
3
) =
ppm Ammonia Nitrogen (NH
3
-N) x 1.2
To express results as Ionized Ammonia (NH
4
+ ):
Ionized Ammonia (NH
4
+ ) =
ppm Ammonia Nitrogen (NH
3
-N) x 1.3
NOTE: If the color of the test sample is darker than the highest color
standard, repeat the test on a sample diluted 1 to 1 with ammonia free
distilled water. Multiply this reading by a factor of 2 to compensate for
the dilution. Read results in ppm Ammonia Nitrogen.
For the most accurate results, repeat steps 1-4 on a blank of deionized
water and subtract any reading obtained from the test result.
Ammonia in water occurs in two forms: toxic unionized ammonia (NH
3
)
and the relatively non-toxic form, ammonium ion (NH
4
+ ). This test
method measures both forms as ammonia-nitrogen (NH
4
+ -N) to give the
total ammonia-nitrogen concentration in water. The actual proportion of
each compound depends on temperature, alkalinity, and pH. A greater
concentration of unionized ammonia is present when the pH value and
salinity increase.
1.
Consult the table on Page 6 to find the percentage that corresponds to
the temperature, pH and salinity of the sample.
2. To express the test result as ppm Unionized Ammonia Nitrogen
(NH
3
-N), multiply the total ammonia-nitrogen test result by the
percentage from the table.
3. To express the test result as ppm Ammonia Nitrogen (NH
4
-N), subtract
the unionized ammonia nitrogen from the total ammonia-nitrogen.
5