HOW THEY WORK:
ETI test strips are designed to measure FFA (Free Fatty Acids) which is a carboxylic acid with a long chain. The more free fatty acids there are in oil, the higher the Acid Value (AV). Acid Value is the number of milligrams of potassium hydroxide (KOH) necessary to neutralise the fatty acids in 1 gram of oil sample. By submerging the reagent end of the test strip for 2 seconds, oil is absorbed and the fatty acids within the oil react with Potassium Hydroxide in the reagent.
After 2 minutes the colour developing chemical compound in the reagent changes dependant on the mg/KOH/g required to neutralise the FFA within the oil. This colour can then be matched with the colour chart on the rear of the bottle. 0-0.5 being IDEAL, 1.5-2.5 being CAUTION and 3.0-5.0 being BAD.