And my water tested 0.0. I tested my tap water (well water) and it tested 0.09. So that told me it wasn't broke and i performed it right. I have been experiencing sluggish growth with my zoas and favia. And I'm confident its because my water is too clean. I turned off my gfo before I went to work yesterday, came home and my shrooms were extremely happy. Will phosphates raise on their own, or can I add something to bring it up to 0.03? I also how often should I test phosphate, once a week?