1 2• Whenever the cuvet is placed into the measurement cell, itmust be dry outside, and completely free of fingerprints, oilor dirt. Wipe it thoroughly with HI 731318 or a lint-freecloth prior to insertion.• Shaking the cuvet can generate bubbles in the sample, causing higher readings. To obtainaccurate measurements, remove such bubbles by swirling or by gently tapping the cuvet.• Do not let the reacted sample stand too long after reagent is added, or accuracy will be lost.• It is possible to take multiple readings in a row, but it is recommended to take a new zeroreading for each sample and to use the same cuvet for zeroing and measurement.• After the reading it is important to discard immediately the sample, otherwise the glassmight become permanently stained.• All the reaction times reported in this manual are referred to 20°C (68°F). As a general ruleof thumb, they should be doubled at 10°C (50°F) and halved at 30°C (86°F).• In order to maximize accuracy, prior to a measurement follow the validation procedure tobe sure that the instrument is properly calibrated. If necessary, calibrate the instrument.STARTUPPrepare the instrument for measurement as follows:• Unpack the instrument by removing the dust protection sleeve from the instrument cuvet holder.• Place the battery in the instrument as described in the “BATTERY REPLACEMENT” chapter.• Place the instrument on a flat table.• Do not place the instrument under direct sun light.