Ron,
Some of my plants are having a problem. The fan leaves on the bottom have started to show yellow spots at te tips and progressively get worse. The spots end up turning brown and gray. It this over fertilization,
nutrient lock up? Or is it a magnesium deficiency? I have leach the system with fresh water for a full 24 hours, have been foliar feeding and and put in new solution. It looks like I have stopped the problem for now. Any advice? Thanks, Bob