you dont have enough air in your dwc... add another air stone, or drop water temp. the burn is most likely coming from ph fluctuations or a lack of phos...
Ph is the real issue tho. The dolomite lime should give u enough cal mag so start with lowering water down to 5.5-5.8. And if that doesn't do it After a week or so then add a bit more cal and mag
Hey problem is mag cuz Ur ph is way too high try 5.5-5.8. Also if Ur using nuts with 5 % cal ull need at least 6 ml to meet cal requirements. use a little pinch of of Epsom salts per a gal too (approx 1 gram), this will do wonders, the extra magnesium will help mobilize other nutrients. If uve...