Orders are shipped within 24 hours. 2-3 days delivery. Free Shipping on All U.S. Orders Over $50. To find out the cost of worldwide shipping, simply add the items to your cart, enter your shipping details, and the cost will be automatically calculated.
In stock, ready to ship
Inventory on the way
Active oxygen | 0.0 - 30.0 mg/l (ppm) | reagent for measurements - DPD N° 4. Shelf life tablet reagents 2 years. ( TbsPD450 )
In Northern latitudes, active oxygen is a particularly popular alternative disinfectant to chlorine. Principally, however, for purposes of measurement what counts is whether the medium used contains persulfate or peroxide. Water disinfected with persulfate-containing media is measured according to the DPD N° 4 method. When using peroxide containing disinfection media, Hydrogen Peroxide tablets are used in connection with the Acidifying PT tablets. In both cases, the “Active Oxygen (O2)“ designation is in fact misleading. It is not the molecular Oxygen that oxidizes (disinfects); rather it is an Oxygen radical which quite quickly combines with an additional radical to form molecular Oxygen (the air one breathes). This is also the main disadvantage to this method; because the disinfection effect does not last long and the effect is rather limited. As a strict rule, therefore, Chlorine is added in regular intervals when Active Oxygen is used for disinfection. Yet with the DPD N° 4 method false readings can then result (when simultaneously using both Chlorine and Active Oxygen), because the potassium iodide contained in this tablet catalytically splits the persulfates and thus the sum of persulfate and chlorine is indicated