It's really kinda early to see that, especially with t-5's. Did you mix all your soil at the same time? Did you pH test it before hand? Nobody ever does the first time.White widow... do I feed it milk? Haha honestly what do I do? Pics are not showing it as well but seems worse in real life, whatever the problem is
Reason I'm asking is calcium is locked out in lower pH ranges, so if soil pH was low starting off, that could be the issue. Another possible is your input water is low pH.