We all know how important it is to maintaining the proper pH.
Here are some tips from Pinpoint
on how to maintain your pH meter
so that it is giving you the critical information you need
to maximize your yields.
Avoid placing the probe in RO or De-ionized water.
Contact with low ionic fluids
can cause the reference fluid in the probe to leak out
and shorten the life of the probe.
Clean the probe tip gently every 34 weeks
using a SOFT TOOTHBRUSH ONLY .
Push the probe tip down into the wet bristles
and rotate the probe 34 times, use Tapwater.
This will clean the inner surfaces of the probe
as well as the sensing glass
and reference junctions.
No other cleaners are necessary, or recommended.
Occasional replacement of the probe is necessary to maintain performance.
The probe should be discarded and replaced
when it can no longer be calibrated with 2 different calibration fluids.
If it takes more than 1 minute
to read between 4.0 to 7.0
then your probe is at the end of it's useful life
and should be replaced.
The useful life of a pH Probe
is approximately 18 months of continuous duty.
Important Points to Remember:
Most pH meters are NOT waterproof
and must be operated on a dry surface.
Liquid contact with the printed circuit board
may cause corrosion and void warranty.
The clear plastic cap must be removed from the tip of the probe
so that pH values can be measured.
A small amount of storage fluid may be expelled;
this is normal.
There may be some white salt
which is Potassium Chloride residue,
from the storage solution and forms
around the clear plastic cap.
This is normal,
and can be washed off
with tapwater.
(avoid contact with distilled or RO water)
Keep the sensing surface of the probe WET at all times.
If the probe is to be transported or stored,
the plastic cap must be filled with storage solution,
or 4.00 calibration fluid,
prior to being installed onto the probe.
Probe should be inserted at least 1 inch into the liquid to be measured.
Probe may be totally submerged if desired.
If several probes are used,
(i.e., pH and TDS, or several pH probes, etc.)
space the probes 34 inches apart,
so that the probes will not react with each other,
and yield erroneous readings.
Clean the sensing glass and reference junctions of the probe,
every few weeks by using only a wet soft toothbrush and tapwater.
Replace the probe at least every 18 months for optimum performance.
Check the calibration often to verify your pH readings.
Place the probe into 2 different calibration fluids,
(e.g. 7.00 & 4.00),
to verify that it can read the 2 fluids correctly.
Recalibrate the meter if either, or both,
of the 2 calibration fluids are displayed incorrectly.
Do not allow air bubbles to accumulate under a vertically installed electrode.
pH Probes
1. Glass body electrode versus Epoxy (plastic) body electrode: Glass body electrodes stand higher temperatures (typically 100 C against 80 C for plastic) and are more resistant to corrosive chemicals and solvents. They are easier to clean and are available in different shapes depending on the application. On the other hand plastic body electrodes are more rugged and the glass bulb is better protected.
2. Gel filled electrodes versus refillable electrodes: refillable electrodes last longer since electrolyte can be changed for repeated usage. The response is faster due to a greater outflow of electrolyte into the sample and therefore less likely to clog. Gel filled electrodes require less maintenance and resist to higher pressure.
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