I had the same problem I was in DWC so I am not sure if it will help out. I kept my ph at around 6.0 and it started spreading. I went and purchased some cal-mag and mixed 1tsp in a gallon of phd water and used it in a spray bottle and sprayed them about 4 to 5 times a day and then added 1tsp per gallon of water to my res two days later they are fine.