The friends who swim in the sea know that the sea water is not only salty, but also astringent and occasionally makes people feel vomiting. This is because the natural sea water contains a lot of chemical ingredients, not only sodium chloride, but also potassium chloride, magnesium sulfate, iodine, iron, bromine, aluminum and dozens of other elements, so we also need to mix with multiple elements when we configure the sea water, not chlorination as some friends imagine. Sodium concentration can be reached to a certain level. Here we introduce the preparation method of seawater in the aquaculture of marine fish.
We usually dissolve the finished artificial sea salt into fresh water to make artificial sea water which is close to natural sea water. Artificial sea salt is mainly made by mixing several salts in a certain proportion. Specifically, sodium chloride, magnesium sulfate and potassium chloride are mixed in a ratio of 3:2:1, so that they account for 90% of the total proportion. The remaining 10% can be replaced by some trace elements. The difference between good sea salt and poor sea salt lies in these 10% trace elements. Trace elements are very important to fish and mollusks, especially mollusks, beautiful corals and sea anemones. Without trace elements, they can not synthesize such bright colors.
In terms of water sources, we should use trapped tap water or underground well water. Artificial sea salt is used according to the salinity of sea water. The salinity of natural sea water is 34% - 35%. So we should make similar salinity. My approach is to prepare artificial seawater of approximate concentration according to the prescribed dosage of sea salt, because the weight of water is not easy to calculate, so the error may be relatively large. At this time, we need to use a densitometer (hydrometer) to measure, according to the "density-salinity-temperature" comparative table (densitometer generally accompanied by this table), to adjust the salinity to the most standard value. Now there are instruments that can directly display salinity, which is more convenient to use.
When the seawater reaches a certain water level, we can open the circulating filtration system, heating system, oxygenation equipment and so on. With the use of nitrifying bacteria, we can measure the water quality every 12 hours. The specific adjustment process will be discussed in future articles.
Matters needing attention:
1. When preparing seawater, don't use metal containers for dissolving seawater salt (neither aluminium nor iron can be used). On the one hand, it is easy to corrode the containers, on the other hand, it will change the ionic composition of seawater after reaction.
2. The newly prepared seawater will be more turbid, which is a normal phenomenon. When the water level reaches, the circulation system can be opened and the turbidity can be eliminated.
3. The filtration system of seawater tank is larger than that of freshwater fish. Adding the water body of the filtration system can keep the water quality stable better.