Hey I saw the yellowing tips you mention, my seedling did this when I tried to put her on 24 hours light and it happened quickly, some of us would advise a 20 or 18hr light schedule, unless 24 is working well now. If you can add a cup on top or bottle for a cheap humidity dome they love moisture at this stage. I also see your night temp is fairly close to the day temps, if you're giving any sort of night, try to cool down by 5-10 degrees probably just a small fan would do it. Go easy on nutes this early on the plants will be happy and your billfold too. Any extra lights you can add cfl or other especially during flowering to boost above the 100watts would probably help out also. From what I understand many small lights are better than just 1- 2 strong ones.
Happy growing.
