The Aqua-Rex is a physical water conditioner designed as an alternative to a conventional water softener. It stops calcium scale from sticking to surfaces by causing it to form on nucleation seeds in the water. This means the scale forms as an ultrafine powder in suspension in the water rather than encrusting pipes and heat exchangers. When installed on existing systems that already have scale in them, it breaks up the existing scale, cleaning out the plumbing system of any old scale. It also partially softens the hot water by stimulating precipitation in suspension. This means there is less dissolved calcium in the water, making it softer. Soaps lather better and the water feels softer on the skin without the slippery feel of sodium produced by a conventional softener. 702-304-2170; www.aqua-rex.com.