User Guide

11
• Whenever the cuvet is placed into
the measurement cell, it must be
dry outside, and completely free of
fingerprints, oil or dirt. Wipe it
thoroughly with HI 731318 or a
lint-free cloth prior to insertion.
• It is possible to take multiple
readings in a row, but it is
recommended to take a new zero
reading for each sample and to use
the same cuvet for zeroing and
measurement.
• It is important to discard the sample immediately after the reading
is taken because the glass might become permanently stained.
• All the reaction times reported in this manual are referred to 20°C
(68°F). As a general rule of thumb, they should be doubled at
10°C (50°F) and halved at 30°C (86°F).
HI 83225 - NUTRIENT ANALYSES
Code Parameter Page
1 Ammonia LR 23
2 Ammonia MR 25
3 Ammonia HR 27
4 Nitrate LR 33
5 Nitrate MR 35
6 Nitrate HR 37
7 Phosphorus LR 39
8 Phosphorus MR 41
9 Phosphorus HR 43
Code Parameter Page
10 Potassium LR 45
11 Potassium MR 47
12 Potassium HR 49
13 Calcium 29
14 Magnesium 31
15 Sulfate 51
PARAMETERS REFERENCE TABLE
50
• Wait for a few seconds and the display will
show “-0.0-”. Now the meter is zeroed
and ready for measurement.
• Remove the cuvet and add
the content of one packet
of HI 93750B reagent. Re-
place the cap and mix
gently for one minute by
turning slowly the cuvet up-
side down.
• Reinsert the cuvet into the
instrument.
• Press TIMER and the display will show the countdown prior to the
measurement or, alternatively, wait for 2 minutes and press READ
DIRECT. In both cases “SIP” will blink during measurement.
• The instrument directly displays concentration in mg/L of potassium
(K) on the Liquid Crystal Display.
• To convert the reading to mg/L of potassium oxide (K
2
O), multiply
by a factor of 1.20.
INTERFERENCES
The following ions do not interfere below the concentrations reported:
Ammonium 10 ppm Calcium 10000 ppm as CaCO
3
Chloride 12000 ppm Magnesium 8000 ppm as CaCO
3
Sodium 8000 ppm
Potassium HR
For samples containing more than 200 ppm of Potassium: first follow
the sample preparation procedure described at page 21 for NUTRIENTS
SOLUTION (HR). Then add to the graduated cylinder 20 mL of the
prepared sample (for HR) and fill the cylinder with demineralized
water from the Demineralizer Bottle up to the 100 mL mark.
Follow the MEASUREMENT PROCEDURE at page 49.
Read the result in mg/L of Potassium on the display and multiply the
reading by 5 to obtain the real concentration of Potassium in your
sample.
POTASSIUM ULTRA HIGH RANGE