With new reports coming out daily, such as the Pew Oceans Report, America's Living Oceans: Charting a Course for Sea Change, reaffirming the dire straits of our marine resources, the recent interest in improved and real-time monitoring of our drinking water resources and large scale international monitoring programs such as the Global Ocean Observing System; the need for affordable, simple and reliable water quality measurement products has never been greater.

Turner Designs has recognized this need and has committed its' development efforts towards such products. Our instrumentation line ranges in price from less than $2K to over $10K to fit many budgets, as well as meeting many different application needs. And, you can expect us to continue to provide new lower priced fluorometers in the coming months.

To meet the needs of making our products simpler to use, and to calibrate, we have added an extensive section to our web site addressing in vivo chlorophyll a measurements.. See In The Spotlight for more information.

Finally, thank you for your feedback to last month's newsletter, and don't forget we still have our special promotion running on AlgaeWatch orders.

Yours sincerely,
Rob Ellison
Director of Sales and Marketing.

Turner Designs Announces E-Support For In Vivo Chlorophyll a Measurements

Turner Designs is pleased to announce the addition of Application E-Support for In Vivo Chlorophyll a Measurements to its web site. Information provided includes: technical tutorials; application specific calibration procedures with videos; and product selection information.

If you have wanted to know how to interpret your in vivo chlorophyll a data, or would like to know more about how fluorometers measure chlorophyll a, or perhaps you would like to know how to calibrate your fluorometer, then the new Application E-Support section of our web site will be one you will want to visit, and bookmark.

Now, you will be able to get access to technical information on in vivo chlorophyll a measurements 24 hours/day, 7 days/week, worldwide. By consolidating answers to the most common technical questions, you have more information available to you than traditional e-mail responses or typical phone support can provide.

To access this new section of Turner Designs web site, click here.

Question:
I am using an Aquafluor and a SCUFA submersible fluorometer to monitor in vivo Chlorophyll and Turbidity levels in several lakes. What type of standards should I use for calibrating them?

Answer:

To calibrate the Chlorophyll channel, the best approach is to use the Solid Secondary Standard, Part No. 2000-901 for the SCUFA and 8000-950 for the Aquafluor. For the turbidity channel, use a turbidity standard between 20 and 100 NTU. You can order the turbidity calibration solutions from APS Analytical Standards.

OEM Fluorometers for Industrial and Multi-Parameter Systems Markets

Turner Designs is the leading supplier of private label fluorometers for integration and resale into Industrial and Multi-Parameter Monitoring Systems. We supply standard and custom sensors to companies marketing industrial monitoring systems, (typically dye tracing), as well as manufacturers of multi-parameter systems where the need is for a widely accepted fluorometer.

We invite you to contact Turner Designs OEM team to discuss your needs to solve a unique application, or monitoring challenge.

For more information about OEM instruments, please visit our website.

Beaver Water District Utilizes the SCUFA Submersible Fluorometer for Managing Watershed

The Beaver Water District in Northwest Arkansas manages the Beaver Lake reservoir and the rivers and streams that feed into it. Beaver Lake provides the source water to thousands of local residents, and therefore monitoring the quality of this water on a regular basis is of high importance to the water management team. Amongst these monitored parameters, chlorophyll a (algae) levels are of considerable interest due to the negative impact that algae can have on the color, taste, and odor of the water. Beaver Water District utilizes Turner Designs SCUFA Submersible Fluorometer to monitor their chlorophyll a levels, which has helped structure their watershed management practices to best minimize algal blooms from occurring in the reservoir.

James Hoelscher is the Laboratory Supervisor for the Beaver Water District. He and his watershed monitoring team of Cindy Harp, Susie Davis and Mistie Ingram utilize the SCUFA to determine relative concentrations of chlorophyll at various depths and locations within and feeding into Beaver Lake. Samples are also sent off to a laboratory where exact concentrations of chlorophyll are determined. The chlorophyll data that they gather assists James and his team in determining the best watershed management practices to undertake that will minimize the likelihood of algal blooms occurring within the reservoir.

James and his team have been extremely satisfied with the SCUFA and the problems it helps solve managing the water quality within the Beaver Water District. He notes that “without the SCUFA, we simply could not perform detailed vertical profiles with such ease of use, general accuracy, and reliability.” Although they utilize a wide array of field and laboratory instrumentation for their water quality analysis, James considers the SCUFA his “pride and joy” since it is “quick, fast, reliable, accurate, precise, and so easy to use.”

Technically Speaking, It All Adds Up...
is a series of articles for people who want to obtain the best possible results from their fluorometer. Last month Technically Speaking described how to optimize your fluorometer installation when monitoring chlorophyll a in a continuous flow setup, using a fluorometer such as the Turner Designs AlgaeWatch. This month's article will describe how algae buildup on the sample cell in the AlgaeWatch impacts the displayed chlorophyll reading; and some cleaning tips to minimize the impact of the buildup.

Determining When to Clean a Fluorometer Sample Cell
Even if you are using the Basket Strainer on the inlet to the AlgaeWatch Sample Cell, described in last month's article, you will still need to clean the sample cell periodically to optimize your measurement accuracy and repeatability. When to clean? If your fluorometer is remotely located, then minimizing the frequency of cleaning becomes an important issue because of the impact on operating expenses, (time).

The following procedure will give you an appreciation for how to optimize the schedule for cleaning the sample cell.

Step 1 - Decide on acceptable change in reading due to fouling buildup.
This is an arbitrary value, and will generally be a value greater than the AlgaeWatch accuracy specification, (±3%), up to a maximum acceptable change in reading due to buildup on the sample cell. For this explanation, it will be assumed that the change in reading due to sample cell fouling should be less than -10%.

Step 2 - Measure without cleaning!
To determine if the fluorometer sample cell needs cleaning, start by injecting some calibration solution and noting the reading - be sure that you don't clean the cell before making this first reading, since the value will be used as a benchmark.

Step 3 - Clean the Sample Cell
Clean the sample cell by inserting the accessory cleaning brush for the AlgaeWatch, and vigorously clean the cell. (The cell is located behind the desiccant plug on the sample chamber, and can be used to confirm how far to insert the brush when cleaning). Continue brushing until the cleaning brush has removed all the debris and/or fouling, (equal to the bristles being clean when the brush is removed ).

Step 4 - Measure the calibration solution
Using the same calibration solution as in Step 2, inject a sample of the remaining solution until the reading stabilizes again to within ±0.2. Note the new reading of the same solution. If this new reading differs from the reading obtained in Step 2 by more than the arbitrarily established value of 10%, then the time from the last cleaning was too long, and appropriate adjustments to the cleaning schedule should be made, (reduce the cleaning interval).

Less than 10% change means that all the data collected since the last cleaning of the sample cell is within the arbitrarily established limits of Step 1.

Note that it is unlikely that fouling buildup has a known relationship with time, (and it will vary with the seasons, etc.). This means that it is not possible to determine a correction factor for the fluorometer readings for the time back to the last cleaning.

To reduce the chance of having to discard data, it is better to clean the sample cell as frequently as possible, noting the change in reading after cleaning, and making appropriate changes to the cleaning schedule.

Next month's article will discuss how the environment affects the measurement of chlorophyll. For more information on cleaning the sample cell, view the video.

ERF 2003
Estuaries On The Edge: Convergence of Ocean, Land & Culture
September 14-18, 2003
Seattle, WA

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