first, after my water has run through my RoDI filter I am getting a reading of .07, does this mean it is time to change something? For about the last month I have been getting increasing amounts of hair algae and I can't seem to determine the culprit. I know that if your RoDI water is not great this can be a cause so is .07 too high? Second how do you add your chemicals. For the last month or so, I have been turning off my main pump so that when I add it, it gets to spread around in the tank itself and nothing gets lost to any filtration. But when I do this my corals never look very happy afterwards. Thanks for your assistance.