[kennymcmack]

We have a ~600 gallon nitric tank at ~30% concentration that we use for passivating stainless steel.  Our procedure mentions that the maximum temperature of the contents shall be 85 degrees F.  Well down here in Mississippi its above 90 most of the time outside and there's nothing much we can do about the tank temperature.  No one knows why the 85 degree temperature is in the procedure. 

Does anyone know why there might be a maximum temperature set on this nitric tank? 
Does temperature affect the effectiveness of the nitric some how? 

Thanks, Kenny.