The LewaPlus design software is a comprehensive tool for ion exchange resins (IX) and reverse osmosis (RO) membrane systems. LewaPlus allows for dimensioning of IX and RO systems under a variety of system configurations, including some unique process configurations only available with Lewatit and Lewabrane product technology.The LewaPlus design software provides a number of benefits to the designer. These include a new user interface to assist in the organisation of design project files, and linkage to data sheets and MSDS documentation (for IX). There is also a single water analysis data entry screen, with RO scaling calculations, suitable for both IX and RO applications. There are advanced RO system configuration options with automatic calculation of a recommended array for optimisation of system sizing. In addition, the software provides an immediate calculation of system performance, including feed pressure calculations and permeate quality on a single screen in the RO module. The output of IX and RO system design parameters and effluent (permeate) quality are displayed in an easy to manipulate printed output.The LewaPlus software also allows the designer to conduct both IX and RO designs inside the same program utilising the same feed water, allowing seamless design of RO permeate to IX feed, or a direct comparison of dimensioning requirements of either technology.LewaPlus is a 32-bit Windows application. It runs on Windows XP, Windows Vista or Windows 7. There are no specific hardware requirements, but it is recommended to use a screen size of at least 1024 × 768 pixels.