Is it a new tank, did you just add fish. If it's just cloudy and a new tank, or just added more fish I'd recommend just letting it takes its natural course. The safest for the fish. If it's an established tank, I'd make sure you have a strong enough filtration system. Needs to circulate the 3 to 4 times an hr.
50-75% water change should clear it up
Why is it getting cloudy? If it's fresh water fish, are you changing water? Are you over feeding? If you are using a filter, can your filter can change flow/min, try increasing the flow. Does the filter need changed?
You can buy something called Purigen made by seachem. It removes impurities and helps clear your water. A small package is usually about 10$ and they are reusable. It also helps if your doing regular water changes and tank maintenance.
you can get aqua clear from aquarium adventures and it works within a few hours
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