Given the info. To be honest man there’s a lot of factors that cause tip damage. What week are they on? 2-3? Might have to little PPM. Or to much. Have you any experience with this strain before? Some like more nitro in veggie some don’t. Can always give it a flush and re feed. I don’t have all the information to accurately explain what is exactly happening. Most cases it’s PPM in some shape or form. 50% humidity is slightly low. 70% -80% is ideal in my opinion. But that’s an opinion lol. Lots of air flow help. Keep me posted man. Would like to see pics after 1 1/2 weeks or after the 2nd/3rd nodes start. Hope this was helpful in some way. Long Hair CO