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Effective water treatment is a complex process involving steps designed to address system-specific problems such as scale, corrosion and fouling. Each category of problem requires its own specialized treatment. That may be the use of biocides to control microbiological fouling, the addition of chemicals to limit the build up of scale, and the use of different chemicals to reduce corrosion.
But it's not enough to implement those measures. Rather, it is essential to monitor the water within the system to ensure that problems are not developing. For example, many biocides are corrosive. If too high a level of biocide is used, it may cause corrosion; if the level is too low, however, the biocide may not be effective at controlling microbiological growth. What's more, make up water conditions can change from season to season, or if a new source of make up water is used.
To ensure that the water treatment program is effective, weekly monitoring is generally advisable. For example, dip slides can be used to keep track of bacteria levels. Although testing involves labor and possibly some equipment costs, that cost is a small price to pay in comparison to the problems it can prevent.