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         Low Flow Sampling or The Newest Technology Called (Fractional Flow®) Made Easy!


1. What is low flow sampling (Fractional Flow®)?

In low flow sampling (Fractional Flow®), a well is purged at a very low rate to minimize drawdown and avoid disturbance in the well, rather than purging a well at a high rate and removing 3-5 volumes of the casing.

2. What are the advantages of low flow sampling (Fractional Flow®)?
Low flow sampling (Fractional Flow®) has a number of important advantages, but they all boil down to better samples at a lower cost. Low flow sampling (Fractional Flow®) minimizes drawdown, turbidity and purge volume. Proactive's® dedicated pumps will not disturb the well water. 

Here's Why:
Less well disturbance leads to lower sample turbidity, which in turn reduces the variability in the sampling results. Purge volume is reduced up to 95%; it can reduce purge time/labor in most cases. Also, it reduces problems related to excessive drawdown and pumped volumes. Dedicated equipment for low flow sampling (Fractional Flow®) saves even more field time and eliminates contamination from other wells and equipment handling.

Did You Know...
Traditional sampling or high flow pumping increases drawdown, turbidity and purge volume. Bailer movement surges and mixes the well and causes increased turbidity.

3. What equipment do I need to low flow sample (Fractional Flow®)?

  • A Proactive 12-volt submersible sampling pump capable of consistently providing low flow rates without agitating the water in the well or altering sample quality.

  • A flow cell to determine completion of purging.

  • A water level measurement device to measure drawdown.

  • And with any of Proactive® pumps, the field technician can now low flow sample (Fractional Flow®) in an easy and cost-effective way!


4. What Is Better, Using A Portable Or Dedicated Proactive 12 Volt Groundwater Sampling Pump?
Any Proactive12 volt portable groundwater sampling pump can be used for low flow sampling (Fractional Flow®), but a portable Proactive 12-volt groundwater sampling pump will require more time and extra procedures compared to a dedicated Proactive 12-volt groundwater sampling pump. First, lowering a portable device into the well mixes the water column between the upper, more stagnant zone, and the screened zone, adding significantly to the time required to complete purging. Second, portable equipment requires cleaning, handling and setup steps; dedicated systems do not. For example, Proactive dedicated 12 volt Sample Champs system is a better choice compared to portable Proactive 12-volt groundwater sampling pumps due to the fact, dedicating pumps will save time, money and increase sample integrity.


5. What purge flow rate do I need to achieve?

Determine a purge flow rate which will minimize drawdown, commonly less than 1 liter/min.


6. How long to purge?

Passing the purge flow through a flow cell measures key water quality parameters, allowing observation of the point when the readings become stable. This commonly occurs within 10-20 minutes, but depends on the well. Sample collection can begin at this point.


 7. How much will it cost?

Dedicated PVC pumps from Proactive® normally reduce costs enough to pay for itself in usually the first round of sampling! Yes, you read that right, usually within the first round of sampling! Another option is to simply rent 12-volt stainless steel dedicated Sample Champs. The renting option is the most economical way to Low Flow Sample (Fractional Flow®) compared to any other groundwater sampling instrument in the world! We at Proactive call this concept "Fractional Flow Technology." 

8. How will low flow sampling (Fractional Flow®) affect regulatory approval of my existing sampling program?
State and federal acceptance of low flow sampling (Fractional Flow®) has been very good. Proactive® currently has thousands of sites using our pumps for low flow sampling (Fractional Flow®). Most of the time, local agencies require only a simple letter for switching over to low flow sampling (Fractional Flow®). For situations where questions or complexities arise, call Proactive® for assistance.

9. How can I get started?
Call Proactive® today at 1.941.243.3930 (Toll-Free at 1.877.99.HYDRO) for immediate, no-obligation assistance. 

Or email us at

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