The length of time it takes a filter to clear up a pool depends on a lot of things, especially what the water chemistry is doing. If the pH and alkalinity are high, the water can filter and clean but the water may still look cloudy. With the right chemicals added, and running the filter I’d give it a week for the water to be great if it was recently opened and murky and green. Otherwise about 24-48 hours should provide results.

Best of luck!