DPD No 3 Test Tablets

Water test tablets DPD No 3

Used to test the total chlorine level in a pool or spa, these tablets offer a quick and accurate way to test your pool or spa's total chlorine level. They come in strips of ten, ten strips per box. Each tablet is sealed in its' own airtight pocket of the strip.

What is DPD?

DPD is an abbreviation of diethyl-p-phenylene diamine. DPD tablets react with pool water containing chlorine or bromine, colouring the water sample various shades of red. The deeper the colour, the higher the concentration of sanitiser. DPD tablet tests have largely replaced orthotolidine testing as this is considered carcinogenic. The DPD tablet No.1 is used to measure free or "available" sanitiser, the useful hypochlorous or hypobromous acid required for sanitising. DPD tablet No.3 is used after DPD No.1 to measure total chlorine or bromine. The difference between the two measurements is the combined chlorine (chloramine) or bromine (bromamine) value. Chloramines are an undesirable form of chlorine which do not sanitise and cause irritation. Bromamines have some sanitising value but do not generally irritate like chloramines. Either though indicates bather pollution.