Looks like nute burn to me. I understand your bewilderment at having a different result when you've used this medium before. Most likely you have a strain that doesn't like a lot of nutes.
grey1223 Reviewed by grey1223 on . First time serious problem . Hello . First thing i want to say is that im not a first time grower , actually this is my 5. grow . I never had this kind of problem . Usualy i dont have any kind of problems but this time ...i cannot beliave it . its so early for this kind of problems :( please help . Im using always same medium like 4 times before, i never had problem with this medium . PH is of medium is 5.5-6.5 . Im watering with filtered water , ph 7.0 runoff ph is 6.7 Rating: 5