I don't know if it is from aerating but it sounds like that may be it. The way I see it if the water evaporates maybe the nutrients go with it? Probably wrong but that's what it's all about, process of elimination I have read that your water can drop or rise in pH day to day. So I would always check it and balance it to what is recommended. I try to keep it as close to 6 as I can. This is my first time growing cannabis and so far for me keeping my pH at 6 has worked very well. Right now I am just waiting for the roots to develop a little more before I move her to a 5 gallon container. I'm just using a premixed soil with Mill's Nutrients. I will let you know how Chief Happy Leaf does though out her life cycle XD Definitely going to sub this thread...