The crab crab pool management points
1. Selection of wintering pools. Pro-crabs are generally wintered in outdoor earthen ponds. Over-wintering ponds should be selected where they are sheltered from the wind, sunny, close to water, and where the environment is relatively quiet, east-west, rectangular or square earthen ponds, water depths of more than 1.5 meters, and clay soil or clay is preferred.
2. Water quality regulation. During the winter of holding eggs and crabs, when the water body is frozen, insert a proper amount of grass handles and break ice before the sun rises every morning to clean the snow on the ice. Focus on maintaining a relatively stable water environment, the main water quality indicators are monitored once every two weeks, salinity of about 25 ,, dissolved oxygen more than 5 mg per liter, pH value of 7.8 to 8.7 as well.
Leaked earthen ponds shall be filled with water once every 5 days to 7 days. The amount of water exchanged shall not exceed 30% of the total body of water to maintain the water level above 1.5 meters. When more than 5°C is reached, fresh seawater must be added and replaced regularly.
3. Feed feeding. Choose nutritious fresh live bait, such as sand, fresh fish, malt and so on. After the pro-crabs hold eggs, with the continuous change of water temperature, depending on food intake, the daily feeding amount is generally controlled to be 2% to 10% of the total weight of the pro-crab. No matter how the surface water temperature changes, as long as there is a pro crab activity, it is necessary to feed it properly. Feed it once a day before sunset, put the feed below the water level along the soil pool, check the feeding situation on the second day, remove the residual bait, and adjust the feeding amount. A variety of bait species to alternate feeding. Water temperature above 8 °C to feed fresh bait and with bait.
4. Daily management. Every morning and evening, one or more patrols are performed to observe the activities of the crabs, the feeding conditions, and changes in the water color; check whether the escape prevention facilities are damaged; check the fertilized eggs of the brooding crabs regularly every half a month. Take and adjust management measures to ensure that the egg-bearing crabs have passed the winter.
We may have ever heard of the Bullet Fixed Focus Camera/ Fixed Focus Bullet Camera HD/ Bullet Fixed Focus Journal Camera/ Fixed Focus Bullet Camera IR/ Fixed Focus Bullet Surveillance Cameras/ Fixed Focus Analog Bullet Cameras, so what is the Bullet Fixed Focus Camera? We know that the Bullet refers to the camera shape, so what about the Fixed Focus? Actually, the Fixed Focus refers to a type of the camera lens. Today let me introduce the camera lens for you.
The camera lens is the key equipment of the video system. The lens' quality (index) directly affects the overall index of the camera. The lens is equivalent to the lens of the human eye. As you know, if there is no lens, the human eye cannot see anything. That is to say, if there is no lens, then the output image of the camera will just be white without any clear image output; which is consistent with the principle of our home cameras.
Actually, there are many classifications for the camera lens. Today please let me introduce one classification for you---the classification according to the structure.
1. The fixed focus lens with the fixed aperture
The lens has only one focus adjustment ring that can be manually adjusted. Rotating the ring left and right can make the image on the CCD target surface clearest. There is no aperture adjustment ring, so the aperture cannot be adjusted, and the luminous flux entering the lens cannot be changed by changing the lens factors, but can only be adjusted by changing the illuminance of the shooting site. The structure is simple and the price is cheap.
2. The fixed focus lens with the manual iris
Compared with fixed focus lens with the fixed aperture, the fixed focus lens with the manual iris has an extra aperture adjustment ring. The aperture range is generally from F1.2 or F1.4 to fully closed, which can easily adapt to the illuminance of the shooting site, and the aperture adjustment is done manually. The illuminance is uniform and the price is cheap.
3. The fixed focus lens with the automatic iris
Compared with the fixed focus lens with the manual iris, the fixed focus lens with the automatic iris has an extra gear-driven micro motor on the iris adjustment ring, and a 3 or 4-core shielded wire is drawn from the drive circuit, then connected to the camera's automatic iris interface seat. When the luminous flux entering the lens changes, the charge generated by the CCD target surface of the camera changes accordingly, thenthe video signal level changes, and a control signal will be generated and transmitted to the automatic iris lens, so that the motor in the lens can perform the corresponding rotation to complete the task of resizing.
4.The electric zoom lens with the automatic iris
Compared with the fixed focus lens with the automatic iris, the electric zoom lens with the automatic iris two extra micro motors. One motor is connected with the zoom ring of the lens, and can control the focal length of the lens when it rotates; the other motor is connected with the focus ring of the lens, and it can complete the focus of the lens When it rotates with control from the former motor. However, due to the addition of two motors and an increase in the number of lens groups, the size of the lens has also increased accordingly.
All in all, it would be helpful to know about the camera lens if you want to know more about the Bullet Fixed Focus Camera and the whole video monitoring field.
Bullet Fixed Focus Camera, Fixed Focus Bullet Camera HD, Bullet Fixed Focus Journal Camera, Fixed Focus Bullet Camera IR, Fixed Focus Bullet Surveillance Cameras, Fixed Focus Analog Bullet Cameras
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