User manual HANNA INSTRUMENTS HI 93703

[. . . ] 11 Sources of Interferences . . . . . . . . . . . . . . . . . . . . . 12 Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 Calibration Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . 13 How To Ensure Accurate Calibration . . . [. . . ] To maximize battery-life the meter is automatically switched off after 5 minutes of non-use. To reactivate it, simply press the ON/ OFF key. MEASUREMENT PROCEDURE: · Turn the meter on by pressing the ON/OFF key. · The meter will carry out a self-test displaying a full set of figures. After the test, the LCD will change to the measurement mode. · When the LCD displays "----" the meter is ready to measure. · Fill a clean cuvet up to one quarter inch (0. 5 cm) from its rim with the thoroughly agitated sample. · Allow sufficient time for bubbles to escape before securing the cap. Note: do not overtighten the cap. 8 · Wipe the cuvet thoroughly with a lint-free tissue (HI 93703-70) before inserting into the measurement cell. The cuvet must be completely free of fingerprints and other oil or dirt, particularly in the area where the light goes through (approximately the bottom 2 cm/1 inch of the cuvet). · Place the cuvet into the cell and check that the notch on the cap is positioned securely into the groove. · The mark on the cuvet cap should point towards the LCD. · Press the READ/ key and the LCD will display a blinking "SIP" (Sampling in Process). The turbidity value will appear after approximately 25 seconds. 9 · Even though HI93703 covers a very wide range of turbidity values, for very accurate measurements of samples exceeding 40 FTU *, Standard Methods require dilution. In such cases, the correct amount of HI 93703-0 or turbidity-free water to be added to the sample can be calculated as follows: Vos = 3000 / T where: Vos = volume of sample combined with HI obtain the final 100 mL. T = HI 93703 reading 40FTU*) (mL) to be 93703-0 to volume of (exceeding E. g. : HI 93703 reading = 200 FTU * 3000 / 200 = 15 mL (Vos) 15 mL (Vos)+85 mL (HI 93703-0) = 100 mL At this point, take a sample of this solution and measure turbidity. The correct turbidity value of the original sample will be: Tn x 100 mL / Vos = Ta where: Tn = new HI 93703 reading Ta = actual turbidity value of the original sample * 1 FTU = 1 NTU 10 HOW TO ENSURE ACCURATE MEASUREMENTS · Each time the cuvet is used, tighten the cap to the same degree. · Discard the sample soon after the reading is taken to avoid permanently clouding the glass. · All glassware used to contain the standards and the samples should be maintained clean, washed with HI 93703-50 cleaning solution and rinsed with HI 93703-0 or turbidity-free water. · Collect the samples in clean glass or plastic bottles, fit stoppers and perform the analysis quickly. If unavoidable, store the sample in a cool, dark place, but not for longer than 24 hours (the sample needs to be kept at room temperature prior to the analysis). · To obtain a representative sample, gently, but thoroughly, mix it before samples are taken. Do not shake (to prevent air bubbles) and do not let the sample settle. · It is recommended to monthly calibrate the meter with the supplied HI 93703-10 @10 FTU* standard or more frequently for greatest accuracy. · Before inserting vials into the instrument, wipe them with HI 93703-70 soft, lintfree tissue. Handle vials so that no fingerprints can get on the areas where light passes (approximately 2 cm/1 inch from the bottom of the vial). [. . . ] If the repair is not covered by the warranty, you will be notified of the charges. When shipping any instrument, make sure it is properly packaged for complete protection. To validate your warranty, fill out and return the enclosed warranty card within 14 days from the date of purchase. Reproduction in whole or in part is prohibited without the written consent of the copyright owner. [. . . ]