Chlorine

The most common form of pool chlorine is calcium hypochlorite. It comes in powder, tablets and sticks. Ensuring that a pool's water is regularly and properly treated with chlorine can go far toward preventing the appearance of clouding, with two parts per million (PPM) of chlorine being the recommended level for swimming pools. You may also need to "shock" your pool (add more than the minimum levels of chlorine) to restore balance and eliminate clouding.

pH

In addition to chlorine, another important anti-clouding chemical used in a pool is a pH balancing and maintenance additive. Ensuring that a pool's pH balance is between 7 and 8 is of vital importance because chlorine itself almost completely disappears when pH is below 7 and works poorly when it's above 8. And a lack of correct pH can help contribute to clouding when a large number of swimmers constantly use the pool.

Process

As far as pH goes, you need to add enough sodium bicarbonate to the water to get it back to the proper pH balance, which can be done either through use of a commercial pool pH restorer or by using baking soda, which is exactly the same as the commercial variety of pH chemical. One pound per 30,000 gallons is the recommended amount for both. To raise pH to between 7 and 8, just add them as needed.

Other Chemicals

Though not as vital as chlorine or pH balancing chemicals, clarifiers and flocculants can be effective ways to clear up stubborn cloudiness. Clarifiers are nothing more than coagulants. They cause extremely tiny bits of matter that may be clouding a pool to bind together so that they can then be filtered out. Flocculants are effective at causing all the matter in a pool to bind together in a big cloud which can then be vacuumed up.

Considerations

When preventing or eliminating cloudy pool water, you must balance chlorine and pH levels. Skimming the pool regularly is also a good preventative. As well, frequently inspecting the pool's filtration system to ensure it's operating efficiently will help. If you need to shock the pool, you'll have to raise the chlorine level above two PPM and allow it to stabilize. If done properly, cloudiness should then disappear.