Enter the weighed dose and the mixed fluorometer reading, then read the volume every later treatment calculation depends on. Method assumptions stay available without competing with the answer.
Model 07 · Open to everyone
1 · Dose0.10 lb PTSAKnown active tracer
2 · MixOne full turnUniform tracer field assumed
3 · Read250 ppbFluorometer closes the balance
Dose, mix, and readField method ready
Diagram controlsInspect a live quantity
Supporting readoutsSix measurementsOpen
Product dosed5.0lb
PTSA activity2.0%
Reading as ppm0.25ppm
Reading sensitivitySolved volume versus fluorometer reading250 ppb selected
Solved volume vs reading
Drag the plot to set the reading. Low readings expand the answer quickly, which is why background and full mixing matter.
Reference
How the system volume model works
Every dose a loop will ever receive is calculated against its volume, and nameplate estimates are guesses. The PTSA tracer method measures the volume instead: dose a known mass of traced product, let it mix, read the tracer, and the dilution solves for the gallons that diluted it.
The instrument above runs the dilution live. The governing relationship is written out below.
A known mass of PTSA-traced product is dosed, allowed to mix, and the tracer is read. The dilution solves for the loop volume: more dilution of the same dose means a larger system.
Product
Traced product dosed into the loop (lb)
Active
PTSA active content of the product (%)
PTSA
Tracer after mixing (fluorometer reads ppb; ÷1000 to ppm) (ppm)
Assumes
Full mixing.
Zero PTSA background.
8.34 lb per gallon of water.
Worked example
Take the room's default case: dose 5 lb of a 2 percent PTSA traced product into the loop, let it mix fully, and read 250 ppb of tracer.
Solved system volume
47,962 gallons
Half the tracer reading would mean twice the volume: more dilution of the same dose means a larger system.
Common questions
How does the PTSA tracer method work?
A known mass of PTSA traced product is dosed, allowed to mix, and the tracer concentration is read. The dilution solves for the loop volume: more dilution of the same dose means a larger system.
What does the method assume?
Full mixing before the reading, zero PTSA background in the starting water, and 8.34 pounds per gallon of water.
Why measure the volume instead of estimating it?
Every glycol target, nitrite residual, and inhibitor dose is calculated against the volume. A tracer measurement replaces pipe length guesswork with the volume the chemistry actually sees.