Many other conditions sometimes cause weakness (see Table: Some Causes and Features of Muscle Weakness). For example, electrolyte abnormalities (such as a low level of magnesium or calcium) can cause weakness that sometimes comes and goes, as well as muscle cramping and twitches.
For swimming pool chlorination, see Swimming pool sanitation. Water chlorination is the process of adding chlorine (Cl. 2) or hypochlorite to water. This method is used to kill certain bacteria and other microbes in tap water as chlorine is highly toxic. In particular, chlorination is used to prevent the spread of waterborne diseases such as cholera, dysentery, typhoid etc.
Chlorine is chlorine, so the chlorine in bleach is the same as the chlorine in drinking water and in a swimming pool. In fact, you can use chlorine bleach to treat a swimming pool or to treat drinking water. A gallon of bleach provides 1 part per million (PPM) of chlorine to 60,000 gallons (about 250,000 liters) of water.