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.
Full Answer. There are both single-celled and multicellular types of algae. As HowStuffWorks points out, in some types of single-celled algae, asexual reproduction occurs, which causes all genetic information to come from a single-parent cell, which it shares with the newly formed daughter cell. Asexual reproduction occurs by means of fission, in which a cell divides into two more cells. In other types of single-celled algae, the method of reproduction is sexual. In multi-cellular algae, reproduction is done in both ways. Generally, one generation of algae will reproduce asexually, and the next will reproduce sexually. This is possible through the use of cells called spores and traditional gametes or sex cells, according to How Stuff Works. Algae are a class of organisms that do not have roots, stems or leaves, but they usually have chlorophyll.