Help! Lower fan leaves drying out slowly at the tips and edges. Doesn't look like nitrogen deficiency to me, but please prove me wrong!

Hey bro. You should always figure out what's going on before reacting. Full strength on nutes is way to high for most growers unless you have a perfect environment even then it creates very high ec levels. When you see problems first thing to do is when they need watering give enough water that you have runoff. Take the first bit of runoff and test the ph and ec. Figure out whats the proper levels of food ec levels your plants require in the medium your growing and make sure your not to much higher or lower. Make sur your ph is where it should be. Fix both those and watch your new growth. Cheers friend