It is important to test your water quality before jobs. TDS meters measure the amount of impurities present in the water. Window cleaners can then determine what water purification method to use. The lower the TDS (Total Dissolved Solids) the more pure the water is. Many pure water systems come with a built in TDS meter, like the AquaPro handheld TDS meter. It comes calibrated and complete with batteries. It is also waterproof and easy to use. There are many other water fed accessories in stock. Browse indoor pure water products, goosenecks, water fed pole brushes and pure water packages.