Measuring Aluminum: Concentration or Ratio?
Al concentration (ppm): the amount of aluminum (mg) in a given amount of wood (kg)
Al:Ca ratio: the ratio of the aluminum concentration (ppm) to the calcium concentration (ppm). e.g.
Al = 1,525 ppm, Ca = 48,597 ppm
Al:Ca ratio = 1,525 ppm / 48,597 ppm = 0.039