Eureka Manta Manual
Page 60 of 67
G2 Sensors
1
How do I know which sensor is which?
Please see D.1.
2
How do I know when I need to maintain sensors?
Judgment gained from observing your field conditions and data requirements tells you when to
maintain sensors. If you are logging data over long periods, the time when you collect your data from
the Manta is a good time for maintenance and calibration. (B.10)
3
Why is it important to check SC reading in air? What should it be?
A well-dried SC sensor should produce a zero reading in air. This lets you know that a one-point
calibration is adequate.
4
Can I see the slope calculation for pH?
Sure you can – just look at the mV readings in your calibration log. But there’s no need to do that
with your Eureka multiprobe because the reference electrode seldom need replacement, i.e. you
need only monitor pH slope for those manufacturer’s whose reference electrodes are always moving
toward the failure that requires replacement of the pH/reference sensor.
5
What is the range of millivolts for each pH solution?
You asked that question because you’ve been taught to worry about pH mV by another multiprobe
manufacturer, didn’t you? Because you have become used to worrying about mV’s because that
multiprobe requires frequent replacement of the pH/reference electrode? With a Manta, just refill
your reference electrode every two months or so and forget about mV’s. You have more important
things to do than worry about mV’s.
6
How do I get the barometric pressure reading for the DO calibration? Do I need to check it to a
certified Barometer?
You can enter an exact BP from, say, your lab barometer (don’t use the weather station’s BP – it’s
corrected to sea level). Or, you can enter your elevation and the Manta will estimate your BP. Or, if
your Manta has a Depth sensor, the Manta can use it to measure BP.
7
Will my Manta also report TDS and/or Salinity?
Yes; please see Section D.8.
8
How often should I change the pH electrolyte?
Electrolyte usually lasts two months or more. But if you are logging data, or monitoring in very low
Conductivity waters, change your electrolyte each time before you recalibrate pH to be safe. You may
learn a better rule of thumb as you review your data. (D.10)
9
How long with my DO cap last?