"Aquaculture is the culture of animals and plants in water."

Board classes of organisms grown include fish, plants, reptiles, crustaceans and mollusks destined for food or non-food markets. Production systems include ponds, tanks, raceways, net pens, suspended cages, clutch bars, and the net bags and bottom nets used on submerged lands for clam production. Water types range from fresh through brackish to salinities exceeding seawater.

Many aquarists, retailers, breeders and wholesalers have recognized the direct relation of water quality and the health and longevity of the aquatic environment. As such, aquarists are more aware of the importance of water testing.

Routine water testing of parameters such as pH, dissolved oxygen, conductivity, hardness, nitrate, phosphates and temperatures, reinforces disease prevention. This is so because any stressful environmental conditions can be detected and analyzed easily.

pH is a measurement of degree of acidity or alkalinity of water. It is measure on a scale of 0 to 14. Technically, pH is defined as the negative logarithms of the hydrogen ion activity or concentration.

pH = -log[H+]

The value of pH 7.0 represents neutrality. Below pH 7.0 is acid and above 7.0 is alkaline. Most natural fresh waters will have pH values of from pH 5.0 to 8.5. Natural seawater has fairly constant pH of about 8.1. Below pH 4.0 or above pH 8.3, plants, fish or invertebrates are unable to survive.

General health and well being of the culture organisms can be attributed to the pH level. Every culture species has a preferred pH range in which it will grow best and breed. Maintaining correct pH is a constant concern for the aquaculturist.

Trans's Eco pH Plus tester is ideal for aquaculture use due to its simple usage and rugged design i.e. drop and shock resistant. Choose WalkLAB microprocessor pH meter TI9000 for those who prefer a better resolution and greater accuracy.

Conductivity is the measure of the total concentration of all dissolved mineral salts in water. This parameter represents the capability of water to conduct current which is directly proportional to the concentration of salts in water.

The dissolved mineral salt content sometimes need to be adjusted in a culture system to prevent other species or disease organism from becoming established. Change in dissolved mineral content may cause an alteration of the culture organism's physiology. For example, the brine shrimp has different nutritional requirements at different dissolved mineral content in water.

Trans's WalkLAB Conductivity Pro meter is an easy to use conductivity meter which measures a wide range of 0.1uS to 100 mS. If you prefer digital pocket size tester, choose the range you required from the Senz TDS /Conductivity testers.

Dissolved oxygen in aquatic culture is one of the most critical parameters. All commonly cultured organism need oxygen to survive. A concentration of 5 mg/l dissolved oxygen is adequate for most culture organism populations. The actual levels of oxygen needed by particular species vary greatly with the size of the animal, the temperature and the stress.

Many factors affect the dissolved oxygen content of water and frequent test for dissolved oxygen is most important. Temperature affects the oxygen-holding capacity of water. As the temperature increases, the amount of dissolved oxygen decreases.

With Trans' WalkLAB Digital Dissolved Oxygen meter, oxygen measurement can now be made in situ. There is no need of a sampling device and a flask to retain water in its natural state for later analysis in the laboratory. The meter has high performance, good repeatability and high accuracy. It measures 0 to 20 mg/l.

Temperature is one of the most important environmental variables for all aquatic organisms. It influences the oxygen content of the water, the primary product which is the source of food in the open sea and the reproduction and growth of all species

Different species have different upper and lower limits of temperature tolerance and temperature above or below this range result in stress. Sudden temperature fluctuations may lower disease resistance of the culture organisms and increase their susceptibility to infections. Although some animals can partially regulate their body temperature, the culturist may still try to maintain an optimal growth temperature so that all organisms' energy can go toward producing more tissues rather than staying warm so that it can remain alive.

A rise in water temperature increases the metabolic rate of aquatic organisms and therefore their energy requirement.

All organisms provide a source of organic nitrogen through their excretory products, the by-products of metabolism, and the breakdown of dead cells and tissues. In most water, there is a natural nitrogen cycle that will make organic and inorganic nitrogen into forms, which can be directly assimilated by phytoplankton and plants.

In the nitrogen cycle, harmful ammonia and nitrite are constantly converted into less harmful nitrate, which in turn is used by plants and algae for food. Biological Filtration replicates this cycle. The level of ammonia in the waste produced by living organisms which are kept in a confined environment such as intensive rearing systems can be significant. In certain circumstances levels may be toxic; these vary with species and depend on pH and the oxygen content of the water. In general, level of ammonia which does no harm to aquatic organisms is less than 0.1 mg ammonia in the form of NH3 per liter.

Besides dissolved oxygen, oxygen reduction potential (ORP) can be used to indicate the activity of Nitrogen cycle. ORP represents the balance of electrons in water. Water with a high ORP is of high quality, containing much surplus oxygen and complete mineralization of all waste organic material. If the ORP is too low, there is a chance that oxidation and mineralization may not occur at all and the waste products accumulate to become toxic substances. Trans' Senz Redox is an ideal tool to measure the ORP value.

Phosphorus, usually in the form of orthophosphate (PO4-3), is also critical nutrient for plants. Phosphate in water comes from the mineralization of decaying cells and organisms as well as from human activities (agricultural, industrial and domestic).

High levels of nitrogen and phosphate result in an increase in the number of higher plants and algae. At night, the plants are using oxygen and the dissolved oxygen in a fishpond can fall to lethal levels. During daylight, the plants will remove carbon dioxide from the water, allowing the pH to rise and cause the ammonium to be converted to more toxic ammonia.