Use of TDS Testr in
Fertilizer Applications
A. Simple determination of when
fertilizer is present in a "Fertigation" line using the TDS Testr 7.
Step 1. Determine the TDS value of your "Fertigation"
make-up water prior to addition of Fertilizer by dipping the OAKTON. TDS Testr 1
into a sample and noting the reading when it stabilizes.
Step 2. As your water runs through your "Fertigation"
line, take samples from the line on a frequent basis, dip the TDS Testr 1 into
the sample and note the reading when it stabilizes. When just water is coming
through, the TDS value will be near or within +/- 0%, depending on contaminants
in the line, of the value found in Step 1. Once fertilizer is present in the
line, the value from your sample will increase dramatically above the value
found in Step 1. The amount of increase will vary from fertilizer type and
concentration. The important thing to note is when a sudden rise occurs in the
TDS value.
B. Accurate determination of fertilizer
concentrations
Note: Choose the TDS Testr 1 if the TDS of the
fertilizer concentrations plus the make-up water is expected to be below 1990
ppm. Choose the TDS Testr 2 if the TDS of the fertilizer concentration plus the
make-up water is between 1.00 and 10.00 ppt.
Accurate determination of Fertilizer
Concentration using TDS Testr 1
Step 1. Make a calibration standard using your
fertilizer and make-up water by dissolving 1 gram of fertilizer in 1 liter of
water. This makes a 1000 ppm (1000 mg/L) standard.
Step 2. Calibrate your TDS Testr 1 by dipping it
into standard and adjusting trimmer so it reads 1000 ppm.
Step 3. Dip the TDS Testr 1 into your fertilizer
mixture and read the concentration on the display.
Accurate determination of Fertilizer
Concentration using TDS Testr 2.
Step 1. Make a calibration standard using your
fertilizer and make-up water by dissolving 5 grams of your fertilizer into 1
liter of your make-up water. This makes a standard of 5 ppt or 5 g/L.
Step 2. Calibrate your TDS Testr 2 by dipping it
into the standard and adjusting the trimmer so it reads 5.00 ppt (which is the
same as 5.00 g/L).
Step 3. Dip the TDS Testr 2 into your fertilizer
mixture and read the fertilizer concentration in the display.