well i think it is a block up i think Sensi Grow part A and B has calcium in it but i can check, and it might be the lock up, i just flushed the water and no running 900PPM. so i will see if that fixes it, those are the only 2 leaves with it, on the entire plant. so yea we will see. the other plant that was also rocking at 1400PPM no signs of anything but i also knocked it down to 900PPM if no sign of improvement i will flush for 1 day and then give it about 800 PPM and see how it does. i mean the root growth for that plant is not that big either it is quite small actually.