First Grow - Double Grape

Started with the flowering nutrients this week watered once at 6.3 PH at a 1/2 gallon each. Plants seem do be doing as expected except for a couple of leaves the tips are turning brown, i assume this is a nutrient deficiency of some kind because its only a couple of leaves? Still haven’t found a diagnosis. The new light still hasn’t come should be arriving next week and ill update the grow.