hey there again, burnt tips is always nutrient excess. In your case it's Nitrogen excess as you can see from the oldest leafs being affected first. This stage is burning and yellowing at the tips, the next stage is lock out of the nutrient. What you want to do is cut back on feeding, only feed NPK every third watering so water, water, feed, water water feed. only feed every 10 days minimum , right now you want to water with plain water until the water just starts to run off, then add 20% more water, and follow a strict wet dry cycle from now on. Hope this helps ! 🚀