No water softener and Im using straight from the tap, but I know our DWP uses well water. Ill have to ck the ppms before nutes, but it running at 900ppm at the moment w/nutes. Its only happening in one out of 3 buckets total. I washed off the net pot with ph'd water and wiped most of the ring that was in the bucket. Water seems fine, just changed over to Veg formula, was thinking it may have been too much Route66 in previous mixture, idk...