LaMotte AM-41 Hydroponics Test Kit - Manual (Page 7)

NITRATE NITROGEN
The Nitrate Nitrogen Comparator measures levels from 0.25 to 10 ppm.
Most nutrient solutions will have to be diluted to bring them into this
range. A 1 to 20 dilution is suggested (see Page 6).
NOTE: Place Dispenser Cap (0692) on *Mixed Acid Reagent (V-6278).
Save this cap for refill reagents.
1.
Fill test tube (0820) to the first line with the sample.
2. Dilute to second line with *Mixed Acid Reagent (V-6278). Cap and
mix. Wait two minutes.
3. Use the 0.1 g spoon (0699) to add one level measure (avoid any
excess) of *Nitrate Reducing Reagent (V-6279). Cap and invert the
tube 50-60 times in one minute. Wait 10 minutes.
4. Insert test tube into the Nitrate-N Comparator (3109). Match sample
color to a color standard. Record as ppm Nitrate Nitrogen.
If the original sample was diluted, multiply the reading by 20. Record
as ppm Nitrate Nitrogen.
PHOSPHORUS
The Phosphorus Comparator measures levels from 3 to 30 ppm. Most
nutrient solutions will have to be diluted to bring them into this range. A
1 to 2 dilution is suggested (see Page 6).
1.
Fill test tube (0230) to the line with sample.
2. Use the 1.0 mL pipet (0354) to add 1.0 mL of *Hydroculture VM
Phosphorus Reagent (5138). Cap and mix. Wait 5 minutes.
3. Insert test tube into the Phosphorus Comparator (5305). Match
sample color to a color standard. Record as ppm Phosphorus.
If the sample was diluted, multiply the reading by 2. Record as ppm
Phosphorus.
POTASSIUM
A turbidimetric method is used for the determination of potassium in the
nutrient solution. It is suggested that the nutrient solution be diluted to a 1
to 5 ratio with deionized water to bring the sample concentration within
the range of the test. A 1 to 5 dilution involves diluting 2 mL of the
sample to 10 mL with Deionized Water (5115PT).
1.
Remove the square inner tube and collar.
2. Fill the round tube to the first line (8 mL) with the diluted sample.
3. Dilute to the second line with Deionized Water (5115PT).
4. Add 2 drops of *Sodium Hydroxide Reagent w/Metal Inhibitors
(4259). Cap and mix.
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