Aquameter
™
Series Instruction Manual
10401-00188 Rev M
Items in the Units column marked with an asterisk (*) can be selected as alternative units of
measurement in the Settings Menu (see section 9:
). Items in
the Units column marked with a dagger (
†
) are auto-ranging, i.e. when the values become
too large to display, the units of measurement automatically re-scale.
On Probe models AP-100, 400, 500 and 600, the pH field will be replaced by ORP
(Oxidation Reduction Potential ) if an OPR electrode is fitted in place of the pH electrode. In
this case, the reading will be shown in mV. This is again controlled via the Settings Menu.
The EC field can be replaced by its reciprocal value, RES (Resistivity), if selected in the
Settings Menu. If selected, readings will be displayed in either Ω▪cm or KΩ▪cm, depending
on the value.
GPS position information can also be displayed in the UK as an Ordnance Survey Grid
Reference. See section 9:
6.2. Trend Indication
To the right of each reading, (except position, BARO and depth), a trend indication is given.
This consists of either an upwards facing arrow (which indicates the numeric value of the
reading is rising), a downwards facing arrow (which indicates the numeric value of the
reading is falling) or a two-headed arrow which indicates a steady reading.
When taking a set of readings, gently stir the Probe, or raise and lower it in the sample (if
there is no natural water flow) until the temperature value is steady. By this time the other
values should be reasonably steady and ready for reading or saving.
Be aware, in order to achieve accurate Dissolved Oxygen readings, the Probe needs to be
either placed in flowing water, or needs to be stirred or raised and lowered continuously to
ensure a constant flow of fresh water over the DO Electrode. If there is no water flow
across the Probe, the oxygen in the immediate area of the DO Electrode will be consumed
and the reading will start to fall.
6.3. Temperature Compensation
The electrochemical properties of all solutions change as the solutions’ temperature
changes. In addition, the response of electrochemical measuring electrodes change with
temperature. It is a fundamental, practical requirement in the field of water quality
monitoring that test measurements taken at different temperatures can be compared.
In order to facilitate this, the Aquaprobe automatically applies corrections for temperature
wherever required.
During calibration of the pH electrode, the variation in the calibration buffer solution due to
temperature is automatically corrected for. The variation in response of the pH electrode
due to temperature is also automatically compensated for. During measurement of pH, the
variation in response of the pH electrode due to temperature is automatically compensated
for.
During calibration of the EC electrode, the variation in the calibration buffer solution due to
temperature is automatically corrected for. During measurement of EC, the readings can be
displayed without any temperature correction, corrected to 20
°
C, or corrected to 25
°
C. See
© 2011 Aquaread Ltd.
www.aquaread.co.uk
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