I finally got the rust spots under control, thanks to everyone's help. Special thanks to
@Alaric for taking me under his wing. The condition did worsen before it got better, and it did stunt their growth. Sounds like it was either a oscillating PH or Mag Def from the RO water or both. Don't really know but draining, flushing & reservicing the rez seem to have corrected the problem. I now add CaliMag to rez and Plants have rebounded nicely. I recently switched to the Lucas Formula, and I really like it. I have been experimenting with some LST, but probably didn't start early enough. Just started Flowering today with 12/12 400W HPS. Picture attached.
Tman
