The so-called bottom sand generally refers to any cultivation medium laid at the bottom of the pond, not limited to silica sand, but still dominated by silica sand. As a bottom sand, there should be conditions, including moderate size, stable physical and chemical properties, and inability to dissolve or hydrolyze harmful or unpopular components during use. Any bottom sand that meets these basic conditions can be called "suitable bottom sand", otherwise it should not be used as bottom sand. Coral sand, for example, is not suitable for bottom sand, because in acidic water, it will constantly dissolve calcium ions, greatly improving the hardness, or in water containing carbon dioxide, it will produce hydrolysis reaction, and at the same time increase the hardness, pH value and KH value, which may cause adverse effects or impacts on water quality.
There are many kinds of aquatic plant bottom sand, but according to different sources, it can be divided into three categories-natural sand, processed sand and artificial sand. Their basic characteristics or differences are described as follows _
1, natural sand _ The series of sand mined from nature is called natural sand, which can be divided into massive rock sand and silica sand, and its sources include coastal sand, lake sand, river sand, sea sand and mountain sand. Natural sand is a granular core formed by grinding rocks or pebbles by wind, rain or water, with high strength, compactness and stable physical and chemical properties. Its advantages are easy to obtain, and can reduce the cost when used in large quantities; But the disadvantage is that it may be mixed with impurities (forged stones), and sometimes it must be removed before it is suitable for use.
2, processing sand _ This is a machined product, or a remanufactured product. Machine-made sand is rock particles made by mechanical crushing and screening, but it does not include soft rock, weathered rock, forged rock and other rock particles that may affect water quality. Commodities are generally stone chips with a particle size of about 2~6mm, which are irregular and unsightly and are rarely used. Reclaimed sand is a product that takes natural rock particles or sand particles as raw materials and then gives them certain characteristics after transformation. For example, Ada black soil, Adapus, TBS Dongfeng 1, TBS Dongfeng No.3 and other basic fertilizer sands. This kind of products have a wide range of uses and applications, but the price is higher.
3. Artificial sand can be divided into synthetic sand, chemical sand and fired sand. Synthetic sand is mainly composed of sand powder or mineral powder, binder and additives (such as pigments) mixed in a certain proportion to make sand particles with required properties. This kind of sand has strong ornamental value, rich color and shape changes (such as white, black and blue), moderate hardness and uniform size, but its activity is low and its roots are loose during use. Apart from being favored by Europeans, it is rarely used in other regions. Chemical sand is mainly produced by chemical industry. At present, the chemical sand products used as bottom sand seem to be only black emery. Fired sand can be divided into sintered sand and fired sand, which are made of suitable soil (such as ruby soil and clay). The main products of sintered sand are calcined red jade soil, AZOO active bed, etc. The main products of sintered sand are ceramic sand, foamed stone and so on.
Ordinary bottom sand and its application scope
1, river sand, a very common thing, I believe everyone will not be unfamiliar. It has little effect on water quality and can be used as bottom sand for general fish culture. The color of river sand varies from place to place, including brown river sand, brown river sand and white river sand. Users can choose different river sands according to different situations. (Application: fish in soft water, such as cichlids, small yellow grouper, fish produced in rivers and rat fish, are suitable for landscaping of aquatic plants)
2. Coral sand, like coral stone, will make the water hard and alkaline. (Suitable for seawater or hard water fish, African cichlids, etc. )
3. Black emery, composed of silicon carbide, is mainly sintered from industrial waste soil. Features: it is extremely difficult to disintegrate (hardly disintegrated under normal use), and it will not release substances to cause water quality noise. There is no nutrition in itself. Advantages: it has strong coloring effect on brightly colored fish, high specific heat (which helps to keep the water temperature stable), and is not easy to produce dust due to disintegration. When aquatic plants are used for landscaping, they can strengthen the landscape and facilitate snail catching. It has a calming effect on timid lamprey, insects such as hydra are not easy to reproduce, black shell shrimp and rose shrimp are more brightly colored, and algae are attached to the shallow layer when algae bloom (it is easy to clean up and shrimp are eaten very clean). Disadvantages: small particle size causes small gap in the bottom bed, and high-temperature sintering will produce needle-like crystals, which is easy to stab the bottom bed. There is no nutrition in itself, and some aquatic plants need root fertilizer, which has a high unit price. If you are unfortunately sucked into the filter screen, it is easy to wear the fan blades. (Suitable for both soft and hard water fish)
4. Silica sand: mostly imported from the United States and the Netherlands, sometimes called Dutch sand. Very stable in water, fine particles, quite ornamental. (Application: fish in soft water, such as cichlids, small yellow grouper, fish produced in rivers and rat fish, are suitable for landscaping of aquatic plants)
5. Yilansha: It is beautiful because of its black and white colors, but the particles are uneven, so it is rarely used in ecological tanks. (applicable: medium and large fish species _ applicable)
6. Glass sand and colored sand: synthetic products with relatively stable performance can be used in small tanks and special tanks, but aquatic plants are not suitable for landscaping or breeding large fish.
7. Ceramic sand: Ceramic sand has little influence on water quality, and there are many bagged finished products on the market.
8. Volcanic sand (aquatic grass-based sand): It is a neutral aquarium sand composed of volcanic rocks. The tiny pores in sand can promote the reproduction and growth of bacteria, improve the nutrient release of bacteria to aquarium sand and promote the growth of plants. It contains about 5% boiling iron, which is a mixed fertilizer of zeolite and iron.
9. Taiwan Province cosmetic sand: neutral, does not change the original PH value of water, and is suitable for bed matching in scenery.
10, ADAPSS(powersandspecial// energy sand): it can provide nutrition for the bed, provide water for the early growth of grass, effectively activate the bed, and is beneficial to the growth of various microorganisms and bacteria. (special for water tank)
1 1, Ada Mud: Ada Red Mud, formerly known as Ada South Africa Mud, is made of natural soil through high temperature and sterilization, which fully embodies the natural beauty of tropical waters.
Ada black mud, formerly known as Ada Amazon mud, is made of natural soil after high temperature sterilization, which fully embodies the natural beauty of tropical waters.
ADA Southeast Asian red mud (some people call it yellow mud) can perfectly simulate the characteristics of Southeast Asian water bodies.
12, Philippine sand: similar to coral sand facies. (Suitable for seawater or hard water fish, African cichlids, etc. )
Second, da ji sand
Dajisha is a Chinese term introduced from Japan. According to its original meaning, Daji sand refers to sand grains similar to subminiature pebbles mined from rivers, streams, coasts or mountains. It is characterized by being larger than ordinary silica sand, with a particle size of about 5~8mm, mixed with white, black and gray particles, round or flat, and without acute angle. Its material is stable, does not affect the water quality, and is very suitable for use as bottom sand (except for the slightly larger particle size). It is the earliest material used as bottom sand. However, due to different places of origin, there are great differences in personality (such as some forged stones doped more or less), so special attention should be paid to the selection.
The composition of large pieces of rock sand mined from rivers or streams varies according to the upstream geology of the producing area. Most of them are produced by weathering of granite. Therefore, feldspar and mica are the main components, and shells and forged stones may also be mixed together. These mixed ingredients have a bad influence on water quality, so it is best to remove them as much as possible before use. Japanese imported and self-produced products (such as Yilan sand and Taitung sand) mainly belong to this type. There are also many applications in architecture.
Large pieces of rock sand mined from the seaside are sand formed by the collapse and fall of hills or coastal slopes in the sea due to wave erosion. The material is close to pure silica sand, and most of the sand particles are almost round with uniform particle size, but the size is uneven, which may be mixed with coral sand. When mining, it must be screened to reach the particle size and washed with fresh water to remove salt before it can become a commodity. Because of the high mining cost, it is rarely used.
Rock sand mined from the mountains is a mixture of sand, clay and other substances. The separated sand grains are mainly composed of quartz and feldspar, and the entrained minerals are mica, amphibole, pyroxene and magnetite. Mountain sand contains about 5 ~ 20% clay. After mining, it must be used by sand selection and washing measures, and the mining cost is the highest. This kind of big rock sand is rare in the market.
To sum up, it can be seen that the source of Dajisha mainly comes from river beds or streams, or the remaining sand and gravel used for construction. This kind of large rock sand is not difficult to obtain, so it is the cheapest. However, because it may be mixed with forged stone, it is best to wash it in acid water before use.
The purpose of acid leaching is to remove the components of forged stone, which can be soaked in acetic acid solution (with poor effect), dilute hydrochloric acid or dilute nitric acid until bubbles (carbon dioxide) are not produced. The purpose of water washing is to remove residual acid and acid leaching components. If you want to choose large pieces of rock sand as bottom sand, it is wise to use large pieces of rock sand that will not affect the hardness and pH value of water.
Third, quartz sand.
Particulate matter with silicate as the main component is called silica sand, which is obviously smaller than Daji sand, and its particle size is about1~ 4 mm. There are two kinds of natural sand and processed sand. Natural silica sand is usually collected from coastal placers and is mainly formed by quartzite or hypersilicate. After years of friction and broken waves, it was washed into the sea and deposited. Because the mined silica sand must be washed and desalted before it can become a commodity, it is also called "desalted silica sand" to distinguish it from "salty silica sand". Another difference between silica sand and Daji sand is that it contains less mica and feldspar, and its main component is quartz sand. High-purity quartz sand is white, but most of it has a specific color because of impurities. The most common commodities on the market are mostly yellow to brown.
The processed silica sand is obtained by mechanically crushing high silica rocks or quartzite, and then sieving. After washing, the refined silica sand contains 99% silica (mass fraction) and contains no forged stone component at all, which will not affect the hardness and pH value of water. The particle size is about 3~4mm, slightly sharp, with high packing density, which can promote the development of aquatic plants and ensure their quality, and the price is higher. Such products are rarely seen in Taiwan Province Province, but occasionally heard in Japan.
Fourth, black soil.
Black soil is actually "sand", not "soil". It is hard for people who have never been exposed to black soil to imagine that it is actually a sandy granular substance with a particle size of 2~5mm, a black appearance and a white matrix.
The most representative black soil is the product of Ada. In addition, Cuihu "TBS Dongfeng 1" also belongs to this kind of product. Basically, they are all acid-coated release agents. Natural acid with pH value of 5.0~6.5 is saturated with natural light stone with heavy water. After drying, it is coated with a film made of black soil as the main raw material. This film is insoluble in water, but has certain permeability to water. Through the difference of internal and external permeability, the natural acid solidified in the pores of the carrier can be slowly dissolved and released through this membrane.
Pebble is a kind of lava, white, filled with bubbles formed by gas, so its specific gravity is very light, similar to water, and some can even float on water, so it is also called pumice. The porosity is as high as 7 1.8~8 1.0%, and it can absorb a large amount of liquid like a sponge. Chemical composition _ silica, 70%, Fe2O3, 5.5%, ferric oxide, 2.4%, alumina, 1 1.50%, calcium oxide, 0.79%, magnesia, 0.29%, Na2O, 4.1. The chemical properties are quite stable and will not have any impact on the water quality. However, its physical properties are a bit poor. When rubbed, its surface will be pulverized, its texture will be soft, and it will easily disintegrate under pressure.
It is no exaggeration to say that black soil is mainly a commodity made for the needs of aquatic plants and tanks. Most aquatic plants (especially those in South America) usually like to grow in weakly acidic water. The "black soil trough" made of black soil can provide or meet such a water quality environment, which is the most important function of black soil. Because the coating outside the black soil can control the slow release speed of the carrier, the pH value of the water body can be controlled for a long time, and the water quality environment can be controlled within the ideal pH value range.
When a sufficient number of natural acid systems released from black soil give full play to their functions, KH buffer system can be completely replaced, so that the original natural buffer system is replaced by artificial buffer system composed of black soil. Therefore, the triangular interaction relationship of KH-CO2-pH will gradually disintegrate, so that the change of CO2 concentration will no longer have any impact on pH, thus making the water quality stable in the pH range of pH5.0~6.5 controlled by acid agents. This method of controlling pH value is more effective and lasting than other methods. In addition, the natural acid released by black soil has the ability to form a chelating reaction to hardness, so it also has the function of softening water quality. Therefore, black soil is widely welcomed by ordinary consumers, but the price is high, but not everyone can afford it.
The acid release function of black soil has a long life. When the carrier gradually releases all the acid in the body, it will lose its original function. Its service life is related to the speed at which the carrier releases the acid agent, which is related to the concentration and integrity of the coating. In black soil, when the coating of sand particles is thin or usually damaged, the acid agent is released faster and its service life may be shortened. Frequent water change often leads to acid loss and shortens service life. The coating is too thick and easy to be damaged by local peeling due to collision, so the coating concentration should be just right.
When the acid release function of black soil fails, it must be updated to maintain its original function, otherwise the failed black soil can only be used as general bottom sand. The disadvantage of using black soil cloth tube is that there will be more dust when it is just bought back, and there may be white turbidity when it is used for the first time. It should be the dust of the wrapping layer or carrier and must be removed by the filtration system. At the same time, after a long time of use, some particles may be broken, or the inclusion layer may gradually peel off, resulting in some muddy black soil.
V. Sand cleaning at the bottom of fish tank
To clean up the garbage in the gap between the bottom sand of the fish tank, you can only suck away the dirt with a siphon. When the bottom sand is seriously polluted, it is necessary to clear the tank and change the water, dump all the bottom sand and conduct a comprehensive cleaning.
Of course, in order to reduce the trouble caused by cleaning the bottom sand, in daily life, the breeder should feed the fish reasonably and reduce the accumulation of food residues in the fish tank, which can also effectively prevent the bottom sand from being polluted too quickly and ensure the environmental sanitation in the fish tank.
Six, the thickness of sand at the bottom of the fish tank
Fish tank bottom sand is a hotbed of beneficial bacteria such as nitrifying bacteria, which is conducive to decomposing fish feces and debris and purifying water quality.
The thickness of fish tank bottom sand depends on two factors: first, plants should be fixed, especially those aquatic plants with large plant shape and leaf shape, which need to be planted to a sufficient depth to avoid floating, and the tubers of tuber aquatic plants should be completely buried; Secondly, as a filter layer, the area attached by beneficial bacteria is large enough to meet the needs of biological filtration.
Of these two factors, the thickness required for plant fixation is easy to grasp, but it is difficult to measure the sufficient attachment place for beneficial bacteria. It is generally believed that the thickness of bottom sand should reach about 5cm, which can meet the above two conditions at the same time.