I am like six weeks into flowering. i have been watering my plants lie 1-2 times a week I give them almost 1/2 gallon each. They are in 3 gallon grow bags, soil. i am using fox farm big bloom. The directions say 4 tablespoons per gallon but the website said 1 per gallon. Now I am seeing that the very tips of my leaves are turning white. Is this nute burn? How should i proceed? am I fertilizing correctly?