Seriously, glasspipes is on smack. All wrong.
As stated earlier, you've over fed the plants.
Based on the understanding that you're more than 50 days into flowering.
My suggestion is to flush through a gallon of water per gallon of soil and then use just water for the next week as required. When the plant is about 5 to 7 days out from harvest flush it again, but with 3 gallons of water per gallon of soil this time. That should finish it up. Your leaves are going to continue to yellow off, but more naturally, after the second flush.
You probably could have done worse, don't trip too bad on the burning. Still though, a learning lesson. Too much Cal-Mag can be quite an issue.