CDS-John Blue's NH3 Flow Monitor Calculator now works on all your devices from your desktop and laptop computers to your mobile phone. The calculator is used to calculate the corrected flow rate to determine the most suitable ball for use in your NH3 VisaGage II Liquid Blockage Monitor System (LBMS). Varying methods of inputs include gallons per minute, pounds of nitrogen per acre, or pounds of NH3 per acre. The calculator is available in both English and Metric units. Instructions for use are available at the bottom of the page.