Guide to Dye Tracers
Dye tracers can be very helpful when trying to map a body of water. Tablets, powder and wax are all different types of dye tracers that perform best in various environments. Check out PE Facts to learn what dye tracer would provide the best detection in your body of water!
Dye tracers are used to color a drop of water in order to track it until it is heavily diluted. Plumbing tracing; pollution studies; mapping water flow and flow rate; leak detection and river, lake and pond analysis all frequently use dye tracers.
Dyes come in various colors such as blue, red and green. Detection levels are measured in parts per billion (ppb). This means there is one part of active dye for every billion parts of water. Fluorescent dyes can be detected visually using a fluorometer or a black UV light. Dyes can still be visually detected without assistance if wavelengths are within the range of 100 ppb. A UV light allows detection at lower levels in the 10 ppb range, and a fluorometer can detect even lower levels of <1.0 ppb. The level of detection may vary under diverse water conditions.
How Fluorescent Dye Tracers Work
The standard reflection of light as a color is what creates the visual aspect of dye tracers. The fluorescence refers to the fact that some chemicals absorb the wavelengths, and rather than reflecting light they emit it. This emission of light can be seen using a UV light or fluorometer. Reflected and emitted lights have different wavelengths; therefore, they may be different colors. For example, FLT green has a maximum absorption of 490 nanometers (nm) and emission of 520nm.
What Dye Form is best for Your Application?
One form of dye that is very easy to use is tablets. There is no measuring involved and it can be detected best visually or with the help of UV light. It usually takes about 3-5 minutes to disperse, so it is best when used in small or medium bodies of water.
Liquid dyes are another simple form to use. They can be easily detected using all three methods, can be used with all water volumes and have the quickest rate of dispersion.
Powders are another alternative that are fairly easy to use. They can be detected visually or with a UV light. They have a slower dispersion rate and are recommended for use in medium or large bodies of water.
The final form of dye available is wax. It is very easy to use and can be best detected visually. They are best suited for long-term flow studies because they have a very slow rate of dispersion. Typically, wax dye is recommended for use in medium bodies of water.
How to Calculate the Size of a Body of Water
A small body of water is generally defined as 20,000 gallons, medium is usually 20,000-50,000 gallons and large is over 50,000 gallons. A gallon of water takes up 0.1337 cubic feet. The following formula may be used to calculate the amount of water in a rectangular tank:
Depth (ft) x width (ft) x length (ft.) and divide by the factor of 0.1337 = gallons of water
How Much Water will the Tracer Dyes Color?
The amount of dye needed for detection may be influenced by many factors but this table illustrates the general estimate:
|Dye Form||Gallons of Water Colored|
1 lb. Powder
How to Choose the Right Dye Tracer for Your Application
The color of the dye being used should be chosen to contrast the background of the water in order to allow for the easiest detection. For instance, a green dye would be good for use in brown, murky waters. Green and red dyes tend to offer the greatest contrast because they are fluorescent in nature. They can also be used simultaneously in dual analysis studies. Blue dye is non-fluorescent and is typically used for decoration, in public waters, or for household systems evaluation. Any color dye can be used in clear water.
FWT Red works well in pH ranging from 5-11 and provides a great contrast to its background. It can withstand temperature imbalances well and, most importantly, it is highly resistant to sunlight degradation.
Green is best used at pH levels between 7-11 and provides a moderate contrast to its background. It can handle temperature imbalances; however, it is not very resistant to sunlight degradation.
Industrial red is another color that offers a great contrast to its background. It works best at pH levels ranging from 5-7 and can also endure temperature imbalances very well. It is very resistant to sunlight degradation; however, it is much less resistant to the absorption of inorganic and organic suspended materials than the other colors. Industrial red should not be used anywhere that it might connect to drinking water. Also, it should not be used where the aquatic ecosystem may be frequently exposed to dye tracers.
If a body of water contains heavy sediment or the soil has a high clay content, FWT red, blue or FLT green should be used. Industrial red should not be used in these environments because it will absorb on to the sediment and clay.
As previously stated, sunlight can seriously affect some dyes. FWT red can last up to seven days while green may fade in only three days. Blue dye may last up to four weeks. You should contact a qualified hydrologist to find out the best dye tracer for your body of water.
Commonly Asked Questions
Q. What is FWT red?
A. It is a specially formulated version of the dye Rhodamine WT.
Q. What is FLT green?
A. It is a specially formulated version of the dye Fluorescein.
Q. Is there a way to remove the dye from the body of water?
A.When mixed with chlorine, any of the dye colors will completely disappear. To do so, add approximately 4 grams of a 12% bleach solution to every gram of product you have in the solution.
Please Note:The information contained in this publication is intended for general information purposes only. This publication is not a substitute for review of the applicable government regulations and standards, and should not be construed as legal advice or opinion. Readers with specific questions should refer to the cited regulation or consult with an attorney.