Hi mate, looking at your diary your PH is way to high. It should be 6-6.5 at all times. Although soil is a great buffer and it is possible to water her with ph 5-8, anything over 7 or under 6 and you start to see nutrient uptake problems. The burnt leaves look like Mg deficiency. But can't be completely sure. That is usually the first to show up if you have nutrient lockout. I hope this helps, good luck and happy growing.