Water Quality
The “no-effect” physical and chemical limits of water supporting most fin-fishes
Parameter / ValueDissolved Oxygen / > 90 mm Hg pO2 (60% of saturation) generally 5mg/L
pH / 6.7-8.5
Alkalinity / 50-200 mg/l as CaCo3
Carbon Dioxide / < 2.0 mg/l
Calcium / > 50 mg/l
Zinc / < 0.04 mg/l at pH 7.5
Copper / <0.006 mg/l in soft water
<0.3 mg/l in hard water
Iron / < 1.0 mg/l
Ammonia / <0.03 mg/l constant
<0.05 intermittent
Nitrite – N / <0.55 mg/l
Nitrogen / <100% of saturation
Suspended Solids / < 80 mg/l
Dissolved Solids / 50-200 mg/l
Temperature / Species specific
Definition of Terms
Carbon Dioxide: dissolved in all water, however of more concern primarily in well water
Alkalinity: measure of ability to neutralize acids in solution (buffer) to the equivalence of bicarbonate or carbonate.
Ammonia Nitrogen: Ammonia-nitrogen is an inorganic, dissolved form of nitrogen that can be found in water and is the preferred form of nitrogen for algae and plant growth. Ammonia is the most reduced form of nitrogen and is found in water lacking in dissolved oxygen.
Nitrite: Nitrite, an intermediate in the nitrogen cycle, is formed during the decomposition of organic matter and readily oxidizes to form nitrate. These processes occur in wastewater treatment plants, water distribution systems, and natural waters. Nitrites are useful as corrosion inhibitors, preservatives, pigments, and in the manufacture of many organic preservative chemicals.
Chloride: Chloride (Cl-) is found naturally in water from salts in solution. High levels of chloride can impact taste and also be associated with corrosion or high sodium content. Water with excessive amounts of chloride can be very toxic to many plants. The EPA maximum contaminant level for chloride is 250 ppm.
pH: (chemistry) p(otential of) H(ydrogen); the logarithm of the reciprocal of hydrogen-ion concentration in gram atoms per liter; provides a measure on a scale from 0 to 14 of the acidity or alkalinity of a solution (where 7 is neutral and greater than 7 is basic and less than 7 is acidic)
Water Harness: Hardness is defined as the concentrations of calcium and magnesium ions expressed in terms of calcium carbonate.
Free Chlorine: The measure of Hypochlorous acid and hypochlorite ions in solution which act as a biological sanitizer.