Water Filtration, Purification & Treatment Systems, Water Management. Aqua Rex is a technology leader in the field of Physical Water Conditioners, alternatives to conventional water softeners. Many of these 'No Salt Softeners have a poor reputation in the USA where many systems have been tried and failed to deliver consistent performance. Aqua Rex is based on a UK product that has over 20 Years experience of being Engineer Specified, Building Materials, Water Softening Systems ...