1. A user-controlled, water analysis system comprising: a sensing device comprising a colorimetric sensor capable of obtaining data for a plurality of water analysis parameters, and sensing device processing means in electronic communication with said sensor; a mobile, user-interactive visual display device comprising user-interactive visual display means and comprising processing means in electronic communication with said visual display means, wherein said mobile, user-interactive visual display device is GPS-enabled and is at the same location as said sensing device, and is in two-way data communication with said sensing device wherein the two-way data communication is wireless and operates using a radio frequency between 2.4000 and 2.4835 Ghz, and comprises communication of water analysis data from said sensing device for processing; an auxiliary chemical product appropriate for analysis of a user-selected water analysis parameter; and a water analysis computer program running on the interactive visual display device processing means; said interactive visual display device processing means being in communication with a database comprising a set of executable test parameter algorithms for converting water analysis data to test result data and from which an available test parameter algorithm is selectable; wherein a selected test parameter algorithm is executed by said processing means of said mobile, user-interactive visual display device to obtain test result data; wherein said mobile, user-interactive visual display device further comprises communication means capable of data communication with cloud-based, data resources, and wherein the water analysis computer program and the executable test parameter algorithms are updatable by said communication means capable of said data communication; and wherein said set of test parameter algorithms is stored on said mobile, user-interactive visual display device or stored in said cloud-based, data resources.