the most trusted name in water testing

Unit Dose Dispenser For DPD Powder

Many of our customers have come to prefer testing for free and combined chlorine using the FAS-DPD method, either because they want to be able to measure as low as 0.2 ppm and as high as 20 ppm or because they have difficulty matching the shades of pink in the standard DPD test. With the FAS-DPD method, a small amount of DPD Powder (R-0870) is added to a measure of sample water, which will turn the sample pink when free chlorine is present. Drops of FAS-DPD Titrating Reagent (R-0871) are then swirled into the sample, one by one, until the water turns clear again. The number of drops it took to reach this endpoint determines the free chlorine reading.

A small plastic dipper is supplied with every 10 g vial of DPD powder in an FAS-DPD test kit. The test instructions say to add two dippers of powder. If you are someone who performs this test several times a day—say a service technician—you will appreciate the convenience of the Unit Dose Dispenser™ (9250) which makes using the dipper unnecessary.

It attaches to the vial of R-0870 as shown below. It can stay attached until the end of the workday, when it should be removed and the white cap on the powder vial resecured.

You turn the crank on the Unit Dose Dispenser once to fill it with the exact amount of DPD powder needed for a test, and a second time to drop the powder into the sample. It's easy, it's accurate, and it will save you a little time on a busy day.

Should powder become caked inside the barrel, rinse it out with non-chlorinated water while turning the crank back and forth to loosen and dissolve the accumulated solids. Repeat the procedure using isopropyl (rubbing) alcohol. Do not soak the Unit Dose Dispenser in either water or alcohol. Let it air dry completely before using again.


Purchase Unit Dose Dispenser (#9250) separately. The dispenser will fit inside our K-1515-C, K-2006, K-2006C, and K-2009 cases.


The dispenser attaches to the powder vial while the vial's own cap snaps to the side, out of the way. Remove the yellow reagent cap and you're ready to dispense.


It's easy, it's accurate, and it will save you a little time on a busy day.