DPD 1 Tablets are used for testing Free Chlorine and are compatible with the 2 in 1 and 4 in 1 test kits.
There are 10 tablets in each sheet. 50 tablets in total.
Keep your tablets up to date to ensure you get an accurate reading.
DPD Tablet Information...
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 DPD1 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.