Bright Dyes Rhodamine WT Dye

The Bright Dyes Fluorescent FWT red dye is ideal for septic inspection applications.


  • Preferred, high strength formulations for medium to large scale visual and fluoremetric studies
  • NSF Standard 60 Certification for use in or around potable water sources
  • Also used to calibrate many YSI 6-Series and EXO optical sensors
Starting At $29.95

Bright Dyes act as a coloring label on each drop of water. As that water or liquid travels, it can be identified at each point on its travel until it reaches extreme dilution. It may be detected visually, by ultraviolet light and by appropriate fluorometric equipment. The dyes selectively absorb light in the visible range of the spectrum. They are fluorescent because, upon absorbing light, they instantly emit light at a longer wavelength than the light absorbed. This emitted (fluorescent) light goes out in all directions. Most common fluorescent tracers are compounds that absorb green light and emit red fluorescent light.

Absorption Resistant
FWT red dye is resistant to absorption on most suspended matter in fresh and salt water. Compared to Bright Dyes FLT Yellow/Green products, FWT Red is significantly more resistant to degradation by sunlight and, when used in fluorometry, stands out much more clearly against background fluorescence.

Questions & Answers
How do I dilute this dye for a 125 mg/L rhodamine standard?
Using this dye, various dilutions can be performed to get to industry standard solutions following the instructions on page 129 of the YSI EXO Manual. 
What is the amount of rhodamine dye in the BrightDyes 20% WT dye, in mg/L?
A 20% rhodamine WT by weight dye solution is approximately 200 g/L.
Can I get a certificate of analysis (COA) for the Bright Dyes Rhodamine Dye?
Yes. A COA can be requested at any time with reference to a specific lot number. Reach out to a Fondriest Environmental sales representative to obtain this document.
What is the specific gravity of the 2.5% WT rhodamine dye solution?
The specific gravity of the Bright Dyes FWT 25 rhodamine dye (2.5% active ingredient) is 1.03 + 0.05 @ 25° C.
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Bright Dyes Rhodamine WT Dye
FWT 25 Rhodamine WT dye, 2.5% active ingredient, 1 pint
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Bright Dyes Fluorescent Red FWT 25 Dye
FWT 25 Rhodamine WT dye, 2.5% active ingredient, 1 gallon
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Bright Dyes Rhodamine WT Dye
FWT 50 Rhodamine WT dye, 5% active ingredient, 1 pint
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Bright Dyes Fluorescent Red FWT 50 Dye
FWT 50 Rhodamine WT dye, 5% active ingredient, 1 gallon
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Bright Dyes Rhodamine WT Dye
FWT 200 Rhodamine WT dye, 20% active ingredient, 1 pint
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Bright Dyes Fluorescent Red FWT 200 Dye
FWT 200 Rhodamine WT dye, 20% active ingredient, 1 gallon
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