In the Lab
Using a beaker or container
Use a non-fluorescent container for your water samples. Note: Certain Plastics may fluoresce and interfere with the sample’s fluorescence.
If using a glass container, place the container on a non-reflective black surface.
Ensure that the probe is more than 3 inches above the bottom of the container.
Ensure that the probe is in the center of the container and has more than 2 inches clearance between the circumference of the probe and the inside surface of the beaker.
Take measurements
Using a different instrument to show the impact of using a clear container versus a dark container on readings:
Notice the amount of orange light being reflected back up to the sensor and the body of the instrument.
It is recommended to use a large enough container capable of allowing at least 3 inches from the sensor face for a submersible to have enough clearance for a reading.
Example image below of a C-FLUOR in a 1 liter beaker:
Before making the instrument completely vertical, it is advised to angle the C-FLUOR in before straightening up to allow air bubbles to escape.
Note: A cost effective method of getting a dark container is using a spare glass container and wrapping with black electrical tape.
Using Shade Cap Accessories
If available, a shade cap in use with the submersible instruments is a valuable asset. Be sure that there is enough water to fully submerge the shade cap as well as the optical face of the sensor for accurate readings. We recommend use of the shade cap as it provides a fixed distance for sample measurement and minimizes affects from ambient light. The Shade Cap also offers protection for the optics and prevents damage from deploying, recovering, or transporting the instrument in fast-flowing environments, and/or from bottoming out in shallow environments
Instructions for the Cyclops-7F and C-FLUOR Shade cap: Microsoft Word - 998-2179_MASTER.docx
Instructions for the C3 and C6p Shade cap: SPECIFICATIONS SHEET
Use a large container for your water samples. Note: Certain Plastics may fluoresce and interfere with the sample’s fluorescence even with the shade cap on.
Ensure that the shade cap has drained of all excess air bubbles by tilting the instrument at an angle before straightening it up.
Take measurements and rinse with deionized water between samples.
Best practices for Calibration Setup
Calibration setup: Calibrating to deionized or ultrapure water and calibration standard or sample of known concentration.
Fill the container full enough that there are more than 3 inches of water from the bottom.
This will ensure that you are able to completely submerge the optical face of the sensor and still have the recommended 3 inches of water above the bottom of the container. If you are using the shade cap you want to be sure that there is enough water to fully submerge the shade cap as well as the optical face of the sensor.
Example image of a clear beaker below for clarity and the recommended for calibration - darkened beaker fully filled to the brim:
Fill another glass container with the Calibration Standard and set aside. This container should also be filled with roughly the same volume of standard as the blank container.
Ensure inserting the sensor into the container is done at an angle and then straightened up to prevent air bubbles from being trapped.
Now your setup is ready for using a datalogger, or the DataBank Datalogger (instructions for Databank), to calibrate the instrument for your needs.
Note: Rinse submersible sensor down if using calibration solution of different concentrations or wipe clean between new solution readings to keep cross contamination risk low.
In the Field
Using a simulated example with a C3, note the usage of the shade cap and weight when submerged. Air bubbles are trapped but escaping through the side vents on the shade cap accessory. If you allow time to completely drain, it will provide best results for sampling in the field. Should your setup lack a shade cap for the submersible instruments, it would be advisable to keep the sensor face down away from direct sunlight and to do your best to mitigate sunlight reflecting back at the sensor.
Some things to note:
Shade caps work best when the instrument is in a vertical position
Ambient light can still overload the sensor if placed horizontally due to the open vents
If organic material builds up inside the shade cap, biofouling will reduce sensor accuracy