High doses of chlorine, like pool shock, can cause temporary cloudiness as it kills contaminants. High levels of pH, alkalinity, and calcium hardness are more likely to cause cloudy water.
Cloudy or milky water after shocking is normal, and the water should clear up within an hour or so. Just make sure your pump and filter are running properly. If you add algaecide, keep in mind that some algaecide contains copper, which can actually make a pool cloudy.
1) After shock - Sometimes pool water looks cloudy right after you apply shock granules such as cal-hypo, or liquid shock, but rest assured it's only temporary. This could be due to change in water balance – meaning your pool water temporarily goes off balance when adding these products.
In most cases, a cloudy pool after shocking is only temporary and should clear up within 24 hours. Keep filtering your pool, add a little clarifier to help, and your pool should be clear in no time. If after 24 hours your pool is not clear, then you may need to look a little deeper for the solution.
Wait until the chlorine level in the water drops down to 1-4 parts per million (ppm) before allowing swimmers back into the pool. If the water still looks a little cloudy after the shock treatment, you may want to use a water clarifier before allowing swimmers back into the pool.
Milky pool water is not safe to swim in and can be caused by things such as poor water chemistry, improper filtration, or low sanitation levels. Milky pool water can be cleared up by cleaning your pool surfaces and filter as well as ensuring all chemicals are balanced properly.
Not to worry, this is normal and should resolve itself in a day or so as the chlorine level drops. Just keep your filter running in the meantime. If it doesn't clear up, either your filter-system is compromised, the rest of your water chemistry is out of whack, or you're using some cheap-ass, low-grade shock.
It's pretty tough to over-shock your pool; shocking your pool two days in a row with the proper dosage for your pool volume shouldn't be a problem – and in fact, is sometimes even needed to rid your pool of algae and other contaminants.
Improper chlorine or pH levels
When the pH levels are imbalanced, it renders the free chlorine ineffective and the levels decrease. Too little free chlorine forms chloramine and it is this combined chlorine that results in your pool's cloudy appearance.
Identify the cause of cloudy pool water.
There are three main causes for cloudy pool water, including poor filtration, chemical imbalances, or environmental factors, like nearby construction, trees, or wildlife. Filter and pump problems can be caused by a range of different issues.
Some of the more common reasons a pool will turn murky include low or no chlorine, combined chlorine, water balance issues, poor circulation, filtration problems, weather events, and increased swimmer use.
What happens if too much shock is added? You cannot overshock a swimming pool or add too much. Adding too much shock or overshocking your pool will kill off algae. The negative of adding too much shock is it will upset the chemical balance of your pool.
To double shock, you will need to add 2 pounds for every 10,000 gallons of water. For instance, if you pool is 20,000 gallons, you will add 4 pounds of shock. Green or Dark Green Pool Water: This means there's a medium amount of algae in your water and you'll need to triple shock your pool.
Give the shock a good 12 to 24 hours to work it's magic. If the algae hasn't cleared up after 24-48 hours, clean and brush the pool and add another shock treatment.