I have read it said to add 100# of 33-0-7 or whatever to a tank. 100 gallon I presume.!!
With a carrier of 2-3 gallons /M you are getting burn. Even with the use of potassium nitrate!
Why in the world are you guys using this much granular-dissolvable fert.? If you are running a rate of 5 gallons /M.........why not reduce the mix by 50% and run only 2-3 gallons/M?
I am mixing 1-50# bag of 46/0/0 only...............in 100 gallons at 3 gallons/m. No burn.
Different grasses maybe as I am bermuda and zoysia.........not any if minimal st. auggie in my area.
I just don't follow the use of more carrier in a hot mixture.......why not reduce the fertilizer mixture and spray less water.!!!!