I am aware that maintaining the proper level of chlorine for CYA level will keep algae at bay. What I would like to know is does increasing the level of phosphates in the water increase the demand for chlorine. I am aware that phosphates do not directly cause a demand as they are stable in the presence of chlorine. However, do phosphates contribute indirectly through the increased organic activity? If someone has a report that has tested this hypothesis that would be great also. Otherwise, I would like to set up a test myself.