Alright everyone I am stumped. This is the second time that this has reared its ugly head. The attached photo is a hi res scan of a leaf clipping that I took off one of my purple grandads that just went into flower 3 days ago.
This stuff was not on any of the plants while they were in my veg room (which is cfl based). If you need details on my setup I have a grow journal posted here:
https://www.rollitup.org/grow-journals/20330-my-first-grandaddy-purp-grow.html
Now I had this on my previous Critical Mass grow which I just harvested out of the same hut. My setup was completely cleaned with H202 and I had most of the tubing replaced after the last grow. Because it is DWC I guess something can be passing through the lines and getting my babies sick but I need to know what it is.
Now the only thing I can think of is light stress. I am noticing that only the large fan leaves are affected but on my last grow it spread to pretty much everywhere.
If anyone can just tell me what this is I would be really happy.