The advantages of using fluorescein for water tracing include its low absorption rate and the fact that it emits a bright green fluorescence, which makes it easier to visualise the progress of your experiment. The disadvantages are that fluorescein is rapidly destroyed by sunlight, fluorescence drops markedly below a pH of 5.5, and many naturally occurring fluorescent materials with similar characteristics can interfere with measurements.

A fluorescein sensor works by sending a light beam into the water to be tested, at a fixed wavelength. This wavelength of light excites the dye which subsequently fluoresces at a known wavelength band. The level of excitation measured is proportional to the amount of dye present in the water.

To use Aquaread's fluorescein sensor, first install it into your probe of choice, then perform a full calibration of the using fluorescein dye. Once calibrated it's good to go. Simply put the probe into the body of water, allow the reading to stabilise and take your measurement.

Using a portable fluorescein probe, or fluorometer, to measure concentrations of the tracer dye in water means that there is no need to collect water samples and conduct laboratory analysis. It's also only necessary to use a small amount of dye, because water fluorescein meters can accurately measure concentrations down to the ug/L level.

There are many applications for fluorescein testing in water. It can be used as a tracer or marking instrument in oceanography, in environmental testing simulations to trace and analyse water leakages or contaminants, and for locating rain or groundwater entry points into the sanitary sewer system. These are just a few examples. Fluorescein testing can be used whenever you need to investigate water flow. It is particularly suitable for use underground where it won't be affected by sunlight.