This guy is just two weeks old and he is living in a GH WaterFarm under a good amount of CF 6500k light. The temps are good and there is a fan gently blowing on it. Two questions, 1) is it looking ok or is there a problem on the horizon? 2) How do I know when to add more nutrient? I do not have a TDS meter yet (its on the way). Is there a rule of thumb about when to add more? Thanks in advance