i’ve recently just started making my own water as i was given an ro system by a family member, i’m using fritz salt to mix but what i’m noticing after yesterday my phosphates jumped from .49ppm to .90ppm after i did a 20% water change and im thinking it might have to do with the filters it self they could be at the point where they need to be replaced but would that have anything to do with a spike in phosphates like that?

