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Fresh Water Ecology Types of Water Water Quaility Tests Hydrologic Cycle River Classification
Water Chemistry Invertebrates Other Tests

There are many test to perform to find out the quality of a body of water. Using chemistry is one of the many ways to perform tests. Listed below are some of the chemistry tests scientists use to determine the quality of a body of water.

pH Value
Alkalinity
Hardness
Dissolved Oxygen (D.O.)
 

pH Value

Ph value is determined by testing the water with a wide range indicator (such as Purple Cabbage Juice) and then comparing the color to a 1-14 scale. Values on the pH scale from 1-6 are acidic, 7 is neutral, values 8-14 are basic. The further the value is from 7, the more acidic or basic the water is. Each aquatic animal prefers a different pH value. However, in general a ph value that is close to neutral (6-8) is good.

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Alkalinity

Alkalinity is closely related to the pH test. Alkalinity of water is related to the actual number of base components and is thought of as the "intensity" of the pH. The less "intense" the water is, the easier it will change pH. A low alkalinity reading indicates that even a small amount of acid could cause a large change in the pH value.

Alkalinity is normally higher in "harder" water. Alkalinity is slowly increased by evaporation with concentrates the source compounds as ratio of water to soure compounds is lowered. Alkalinity is reduced naturally by bacterial action. Bacteria produce acidic compounds that reduce the alkalinity of the water.

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Hardness

Hardness is a test that is preformed to determine how "soft" the water is. Hardness is determined by how much calcium carbonate the water has. The more  grains/gallon there are, the softer the water is. A hardness reading of more than ten (10) grains/gallon of calcium carbonate is considered "soft" water.

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Dissolved Oxygen (D.O.)

Dissolved Oxygen is the amount of oxygen that is dissolved in the water. Fish, plants at night, and other aquatic animals use oxygen. The more oxygen there is the better. The table below shows the saturation levels for fresh water. Warmer water can hold less oxygen than cold water.

Table source: http://www.vcnet.com/koi_net/do.html

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Fresh Water Ecology Types of Water Water Quaility Tests Hydrologic Cycle River Classification
Water Chemistry Invertebrates Other Tests