Clear water is free of particulate matter. When particles of dust, dirt and other matter become suspended in clear pool water the water takes on a cloudy appearance. The degree of cloudiness is determined by the amount of suspended matter. Normally, the filtration system will remove suspended matter and maintain good water clarity. Failure to maintain a filter (lack of backwashing) and insufficient filtration (less than the minimum time recommended by the manufacturer) are two factors which contribute to water cloudiness. Extreme cases such as mud slides and incorrect use of chemicals can result in the pool water taking on the appearance of pea soup.