Individuals with normal color vision will see a number, while those with a deficiency do not see it. On some plates, a person with normal color vision may see one number, while a person with a deficiency sees a different number.
Your phosphate level should be at or below 100 parts per billion (ppb). If your water chemistry and phosphate levels seem to be in check, one potential cause of the cloudiness in your pool could be dead algae. Phosphates are the food supply for algae, thus high phosphate levels promote algae growth.
Fertilizers may also cause the excited growth of both aquatic plants and weeds. One pound of phosphorous added to lake or pond water can produce more than 100 lbs. of new aquatic plant life, which will compete with other plants and animals for oxygen.