GMSgrowsanswered grow question 4 years ago When things start to happen is when you really need to know what your medium is at in terms of ec and ph. A lot higher ppm than what you feed in your runoff then you have some lockout happening. Ec ok and ph ok then you know it's a deficiency starting and you need to either feed more or add a little cal/mag if needed. So check your runoff ph and ec levels and go from there. Cheers friend