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.
Regardless of how it happens, if phosphates are allowed to remain present in pool, spa, or pond water, they will be reduced to orthophosphates, which are the only form of phosphates that algae can digest. Orthophosphate levels should remain below 100-125 ppb (parts per billion).