In one sentence, describe what the following article is about:

Look for chlorine solutions designed to shock your pool at your local pool supply store or online. Make sure it is safe for use on all pool types, including salt water pools. Make sure the chlorine and pH levels are correct in the pool. Check that the calcium, alkalinity, salt, and stabilizer levels are correct as well. This will ensure shocking the pool will not cause any staining or damage. Shocking the pool with chlorine is a good way to prevent the water from becoming cloudy and polluted if you are having a lot of people in the pool. It's also a good way to give your pool a deep clean once a year. For a standard size salt water pool, you may use 3 pounds (1.4kg) of chlorine per 1,000 gallons (3,800L) of water. Check the manufacturer's instructions if your pool is smaller or larger than the standard size. Make sure the filter system is working and the pH is between 7.2-7.4. Add the chlorine a small amount at a time around the edges of the pool. Let the chlorine dissolve into the pool water. Use a test kit to check the chlorine levels in the pool. Make sure the chlorine levels have dropped and the water is safe to swim in before you use the pool.
Get chlorine to shock the pool. Test the levels in the pool. Determine the right amount of chlorine. Add the chlorine a little at a time. Wait 8 hours and test the chlorine levels before using the pool.