Successful cooling tower operation and performance involves a delicate balance between (1) keeping the dissolved solids (such as calcium, magnesium, chloride, and silica) in the water from causing too much scale and/or corrosion and (2) conserving make-up water. It’s expensive, inefficient, and environmentally irresponsible to continuously dilute cooling tower water with an abundance of make-up water just to keep the ratio of minerals down. But how do you decide how much make-up water is needed to keep minerals within a tolerable range?