This year I upgraded from a stockpot rocketstove at 1-2 gph to a 2x4 with AUF at 8-10 gph. it took me about 120 gallons to sweeten the pans (i run a little deeper due to draw off valve) to begin this season but now when i draw off, my syrup has a ton of niter and is very dark. I did draw off some early in the year about 214 degrees and finished on propane stove and was a nice amber color but now i am drawing off at 218 degrees and it is very dark.

What could i be doing wrong? is this normal for the extent of time is was over heat? sap was slightly cloudy but not to bad

Thanks for the help