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pH

By , About.com Guide

Definition: pH refers to the measuring unit indicating the degree of acidity of water. The degree of acidity or alkalinity is determined by the relative amounts of acids and bases in the water. If both are present in equal proportion (as in pure water), the ph is neutral or 7.

If there are more acids than bases, the water is acid (pH below 7). If bases predominate, the water is alkaline or basic (pH above 7). Aquarium waters are usually in the range of 6.0 to 8.5, depending upon the environment being replicated.

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