A good rule of thumb which applies in all things in life "measure twice cut once". How that applies in this situation is you need to get a handle on why the tips are burning/you're getting spots before doing anything, and so for the time being waiting and watching is called for.
On the point of not getting many responses I'd like to respond honestly: You need to start keeping a better log. What are you feeding, when are you feeding, what's the source and PH of your water, what's the PH of your runoff, have you made a slurry to test the PH of your soil? What are your temps, daytime, nighttime. What's the room humidity? People will be more likely to answer if they have enough information to at least be able to intelligently guess. I really don't mean this to be a dick, I'm trying to help you.
From what I'm seeing in the pics they look good, nice and healthy.