Dealing witht the same Copper spots you have, it's on two of my six plants, all on the same feeding schedule (week 5 of 12/12, FF at 1/2 strength every 3rd feeding, OF Soil, 2gallon smartpots, 68 watt 2800K CFLs from HD, switching to 600HPS next week).
Let me know if the flush works, I'm just going to water as normal but no nutes for a good week, some things I have read make me think a little Cal-Mag is in order but don't have any yet.
Let me know if the flush works, I'm just going to water as normal but no nutes for a good week, some things I have read make me think a little Cal-Mag is in order but don't have any yet.