EXO Correlation - Total Algae

EXO Correlation - Total Algae

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EXO Correlation - Total Algae

This video covers the cells/mL correlation for the EXO Total Algae sensor using Kor Software.

Timestamps of specific moments of the video

  • 0:00 – Overview
  • 1:44 – Building the correlation in Kor

Video Transcript

In this video, we will build a cells per milliliter correlation with RFU measurements collected by the EXO Total Algae sensor. RFU stands for relative fluorescence units. We will show you how to perform this function in Kor Software, but you can also use the Kor Mobile App.

The EXO Total Algae sensor can output values in RFU and µg/L. If your project requires results in cells/mL, you should perform this correlation. We will compare the RFU results from the sensor to cells/mL results determined by independent lab methods. This should be treated as a supplement rather than a replacement for laboratory analysis.

Please keep in mind that your results can vary greatly between different algal populations, seasonality, and other factors. You will need to determine for yourself what the best sampling methods will be for your project.

We recommend collecting your sample as close to your intended deployment location as possible so that your correlation will be representative. To build my correlation, I decided to collect a site sample and perform a 10%, 1%, and 0.1% dilution. I have analyzed my samples using microscopy to determine the cell counts.

Before beginning, make sure your Total Algae sensor is calibrated. Please refer to our EXO University calibration videos for more information. Next, use the EXO Total Algae sensor to measure the RFU value for each sample. The lab results and EXO data will be entered into the software to build the correlation.

In Kor, navigate to the Instruments and Sensors tab, select the Total Algae sensor, then select “Build my own cells/mL relationship.” The other option, “Use legacy cells/mL relationship,” uses an algorithm to tightly match EXO data to legacy 6-Series sonde data, which may be useful to compare algae data between EXO and 6-Series. If you need to use this method, be sure to verify the data using grab samples analyzed by a lab. Once you’ve selected to build your own relationship, use the table below to enter the RFU measurement along with the corresponding cells/mL value of your sample. Click Apply Sensor Settings, then click Yes.

The software will derive the relationship between the columns you entered and apply coefficients to the sensor measurements in order to deliver a cells/mL output. It is important to validate this relationship during seasonal and event-related changes by collecting grab samples for comparison against the sensor data.

Please check out our other EXO University videos, and thanks for watching!

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