For the first time, I noticed some black stuff in my developer. I use Zone VI developer with both Kentmere FP VC and Arista.edu PWT papers intermixed. I use the single tray method of processing so there is little likelihood of contamination. It does not look like a precipitate, more like black specks or filaments that float in the chemistry. They don't seem to affect the prints at all but I don't like it. Any thoughts about why I am having these black specks? Thanks.