1. The presence of phytoplankton ponds are basically indispensable.
Phytoplankton are part of a community of microbes that play a role in arranging the desired culture conditions. Besides being able to utilize the remaining nutrients, the presence of phytoplankton also reduce the intensity of light, produce oxygen, stabilizing the temperature as well as contributing to the needs of nutrient for organisms maintained. In this type of farming is increasingly diverse, phytoplankton management model should be handled so that got the ambient conditions at a particular density which is the ideal size. It must be realized also that most water quality problems is the resultant of several factors that initially the effect of the presence of phytoplankton were not managed well.
2. Phytoplankton will be on the desired condition when managed and addressed various fluctuation factors that influence the growth.
In general, plankton are colored green or yellow would be more easily maintained than the brown. In ponds with very low salinity levels, the type of blue-green algae will likely emerge. This type is not so contribute to the dissolved oxygen content and even tends to harm the fish / shrimp were maintained.
3. The common problem that often arises in the early days of the death of plankton production is due to lack of nutrients or CO₂.
This condition can occur suddenly and leave little plankton alive. Plankton die will cause the appearance of foam in large quantities on the surface and also deposit the material at the base. At the end of the maintenance period, the problems usually associated with excessive density. If plankton is too crowded and the water is not aerated continuously mostly plankton will die because they do not get enough light. Death often occurs because of changes in water quality dramatically as the heavy rain.
4. To maintain the plankton stable condition, it is necessary to add a number of nutrients, CO₂ and light.
Nutrients may be added in the form of inorganic fertilizer with a dose of 3-5 ppm. CO₂ is supplied from the atmosphere, respiration pets, phytoplankton and bacterial respiration, alkalinity and calcification. The penetration of sunlight can be improved by turning the water to the mill or reduce the density of the water replacement.
5. Replacement of water is the easiest way to lower the density of plankton in pools managed closed system.
In a pool that uses a closed system, the use of chemicals is often done to control density. To watch out for the type, dose and effects of these chemicals when applied. In general, the type used is BKC (Benzal Konium Chloride) at a dose of 0.1-0.5 ppm and formalin at a dose of 10 -20 ppm.
Liming
Liming was made during the preparation of the pond. Liming is done if the land base reacting an acidic (pH <6.0) in the manner and the proper dose not harm the fish life. Liming is intended to improve the pond bottom soil pH to neutral (pH 7.0) and can serve as a disinfectant. Dosage should be adjusted to the conditions liming soil pH basic and types of lime used. A type of limestone used may be whiting, quicklime, limestone walls and lime carbonate / limestone rollers.
In the following Table 5. The listed doses per hectare pond liming.
