1. Alkalinity: This is the sum of components (mainly bicarbonate, carbonate, and hydroxide) in the water that tend to elevate the pH of the water above 4.5. These factors are characteristic of the source of water and the natural processes taking place at any given time. Alkalinity represents the buffering capacity of water and its ability to resist a change in pH. Alken-Murray recommends alkalinity above 75 mg/L to offset acid produced by bacteria nitrifying ammonia.
2. Ammonia: Ammonia nitrogen (N) is present in variable concentrations in many surface and ground water supplies. A product of microbiological activity, ammonia when found in natural water is regarded as indicative of sanitary pollution.
The USEPA recommends a limit of 0.02 ppm as NH3 in freshwater or marine environments. Total ammonia levels, at this limit, can range from 160 ppm at pH 6 and temperature of 5 degrees C to 0.06 ppm at pH 9 and temperature of 25 degrees C.
If large quantities of fish are suddenly added to the water body (such as during stocking), the ammonia level can spike because the natural bacteria that degrade ammonia are slow to reporduce (having a 14 day cycle), so it is best to add a seeding quantity of Alken Clear-Flo 1100 or Alken Clear-Flo 1200 at the same time you add your new fish, to avoid this problem.
CHEMetrics kits recommended: K-1510: 0-1 ppm & 1 - 10 ppm
3. Carbon Dioxide: Carbon dioxide (CO2) is present in water supplies in the form of a dissolved gas. Typically, surface waters contain less than 10 ppm free carbon dioxide while ground waters may have much higher concentrations. Dissolved in water, CO2 forms carbonic acid which lowers pH.
4. Chloride: Chloride is one of the major anions to be found in water and sewage. Its presence in large amounts may be due to natural processes such as the passage of water through natural salt formations in the earth or it may be an indication of pollution from sea water intrusion, industrial or domestic waste or deicing operations. Potable water should not exceed 250 mg/L of chloride. When calcium or magnesium is the cation, up to 1000 mg/L can be tolerated without a salty taste to the water.
5. Dissolved Oxygen: Vital to aquatic life, oxygen enters the water by diffusion from the atmosphere or through plant photosynthesis. Actual solubility is directly proportional to the partial pressure in the gas phase, to salt concentration and temperature. The dissolved oxygen level in water is constantly changing and represents a balance between respiration and decomposition that deplete oxygen and photosynthetic activity that increases it. Organic waste may overload a natural system causing a serious depletion of the oxygen supply in the water that in turn leads to fish kills. Likewise, eutrophic waters, that is those rich in nutrients, achieve the same result through causing massive proliferation of algae (algal blooms) whose eventual decomposition uses up the available dissolved oxygen.
Recommended minimum dissolved oxygen levels for fresh water fish are as follows:
* Reference for shrimp is page 124 Marine Shrimp Culture: Principles and Practices edited by Arlo W. Fast & L.James Lester
6. Nitrites: Nitrites occur in water as an intermediate product in the biological breakdown of organic nitrogen, being produced either through the oxidation of ammonia or the reduction of nitrate. The presence of large quantities of nitrites is indicative of waste water pollution. The level considered ideal for marine fish is between 0.01 and 0.04 ppm.
Levels exceeding 0.55 mg/L (ppm) nitrite-nitrogen can cause 'brown-blood' disease in finfish.
7. Nitrates: Nitrates occur in water as the end product in the biological breakdown of organic nitrogen, being produced through the oxidation of ammonia . Although not particularly toxic to fish, excess nitrates in the water is often used as an indicator of poor water quality. Under anaerobic conditions, such as in the sludge or soil at the botton of a pond, lake or aquarium, denitrification can be used to convert nitrate back to nitrite and from there to nitrogen gas, removing total nitrogen from the aquatic system. In marine environments, levels of 0.1 to 0.2 are considered ideal.
Levels exceeding 50 mg/L (ppm) nitrate-nitrogen are considered unhealthy for lakes.
Levels from 10 mg/l to 40 mg/l indicate poor water in aquariums, depending on the species being raised.
For larger, seriously polluted ponds, lakes, etc., also use: K-6902D: 0 - 25 ppm & 25 - 125 ppm
8. pH: By definition, pH is the negative logarithm of the hydrogen ion concentration. It is in effect an "Index" of the amount of hydrogen ion present in a substance and is used to categorize the latter as acid, neutral, or alkaline (basic).
9. Total Hardness: The Total Hardness of a water represents primarily the total concentration of Calcium and Magnesium ions expressed as calcium carbonate. Hardness may range from zero to hundred of parts per million, depending on the origin of the water or the treatment to which the water has been subjected.
10. Density: The amount of crowding each species of finfish and shellfish will tolerate varies between species. For the majority of finfish, the limit is 0.2 to 0.5 lbs of fish per inch of body length per cubic foot of rearing space. When the tolerable limit is exceeded, fish will exhibit signs of stress including darkening of body color, "clubbing" of gills, fin nipping or loss of tissue between the fin rays and reduced immunity to disease. Shrimp and prawns will also become more susceptible to disease when over-crowded.