Portable water analysis instruments, namely, meters to measure pH, chlorine, alkalinity, cyanuric acid, active oxygen, bromine, chlorine dioxide, ozone, hydrogen peroxide, water hardness, urea and PHMB; photometric instruments for measuring pool water quality; handheld photometers for measurements of pH, chlorine, alkalinity, cyanuric acid, active oxygen, bromine, chlorine dioxide, ozone, hydrogen peroxide, water hardness, urea and PHMB in swimming pools; photometric water analysis testing devices for analysis of swimming pool water