Supply & Delivery Of Ready To Use Chemical Reagents Suitable For Direct Reading The Concentrations Of Fluoride, Nitrate, Sulfate And Iron In Water Samples (Drinking) On Pre-Programmed And Pre-Calibrated Colorimeters/Photometers & Spectrophotometers Of Hach Make To The Water Testing Laboratories In Rural Water Supply & Sanitation Dept., In Andhra Pradesh.