Swimming underwater where can I sell it

What instrument can detect whether the water in the swimming pool is dry? Where can I sell it
 Of course, Shanghai Haiheng water expert brand special swimming pool detector is preferred. The dz-y swimming pool detector produced by Shanghai Haiheng has a full Chinese operation interface. Easy to use and operate. It can measure 8 parameters of residual chlorine / total chlorine / combined chlorine / turbidity /ph/ temperature / urea and cyanuric acid. The portable aluminum alloy box is not easy to be damaged and has the functions of data storage and printingWhy are people prone to cramps when swimming underwater? How to avoid it
There are three reasons why people get cramps when swimming underwater: they do not do enough warm-up exercise, and suddenly jump into the water. The lower water temperature stimulates the contraction of skin, muscle and blood vessels, which can lead to cramps; Exercise time is too long, energy consumption is too much, lactic acid accumulates in muscle, causing cramps; Too low water temperature can also stimulate musclesWhy don't people sink into the water when they swim in it
The most common mistake many beginners make is that their whole body is tilted in the water. His lower body sank in the water. How can you swim in such a physical state? If you can't swim, how can you not be tired? How can you swim fast and far? How can you learnIs it better to swim underwater or on the water
Ask someone to observe you from shore or underwater and give you feedback. When you need to breathe, turn your head out of the water (nose up). The head should be hidden in the water, and only the face should come out of the water. See basic training for other movements. If you are satisfied with this exercise, try backstroke or freestyle. If you want to swim fastHow do you stay underwater while swimming? It's easy to float every time you dive to the bottom
When swimming, if you want to stay underwater for a long time, you must not relax your body. On the contrary, if you want to float on the water, you must relax your body. If you want to stay underwater, you must use your head and waist to drill down hard, so that you can stay underwaterSwimming in the water
For example: there are some stones in the water There are some stones in the water. Please put these stones into the wate. Please put these stones into the water. Because swimming itself is in the water, there is no need to add "in the water": she is swimmingCan you open your eyes in the water
Swimmers can open their eyes underwater. Opening their eyes in the water may cause irritation or foreign body sensation and other discomfort symptoms. Not everyone can open their eyes in the water. When swimming in the water, it is often necessary to open your eyes to see the object in order to identify the direction and avoid obstacles in timeDo you exhale underwater with your nose or mouth
Both the nose and mouth can be used. Exhaling with the nose can control the gas flow. At the same time, it can prevent the bubbles generated by exhaling from the mouth from entering the nasal cavity, and prevent the nose from inhaling water and causing choking. Finish exhaling during underwater swimming. Don't hold your breath until you can't hold it, and then suddenly surface to exhale. If you inhale on the waterWhat are the disadvantages and benefits of swimming in the sea
Before swimming, you must be ready to go into the water. First, warm up the body. Second, let the body adapt to the water temperature to avoid the occurrence of cramps or muscle injuries. In addition, swimming consumes a lot of energy to avoid excessive exercise, and exhaustion may also cause drowningHow do you swim in the water
Keep in mind that the goal is ahead. When entering the water, the hand should be in front of the chest, stroke to the chest, and then accelerate backward to the side of the body to exit the water. Viewed from the side as an S-shaped curve. Balance the force when you alternately pat your feet down and push them back. When you swing your head sideways to breatheWhen swimming, you can't stay in the water for more than a few hours
Generally, the duration of swimming should not exceed 1.5~2 hours. The skin usually has three response periods to cold stimulation