Test Tablets (100 DPD No.1 Rapid desolving). Lovibond DPD No.1 test tablets are a testing reagent, testing for chlorine or bromine using a suitable test kit (please email us via our contact us page for information on purchasing test kits). Always read and adhere to the instructions on the pack and never directly mix chemicals. Don't forget, the price you see is the price you pay not a penny more!