I amended the hell out of the Ocean Forest mix and still don't have any burn other than maybe just some tips of fan leaves but hardly any burn. I also don't think I have seen people complaining of any burn with the Happy Frog which is not nearly as hot as FFOF but it really does depend on your strain because I have seen pure blueberry plants claw like a bear and burn up at 400 ppms of any nutrient solution fed to them in soil while I have fed Shishkaberry or Sweet Tooth plants 1000 ppms or more and they were still hungry afterwards. GENETICS, growth rates, temperatures, plant health, lighting and many other factors come into play in the whole "burn" the plants equation.