Mini mandarin punch auto

I said I had no problems last week, would seem by saying it I wound up having what I believe to be nutrient burn, as a newb I was mixing the nutrients per the instructions but I've been told most nutrient instructions can be a little hot. In the space of a couple of days a few leaf tips curled and went crispy so the mandarin punch auto and the lemonade OG auto have been on plain water for the last 3 days in a attempt to flush a little. I plan to resume feeding at half strength. Apart from the nutrient issues not much has changed over the last 7 days with just a little bit of bud enlargement