Measuring turbidity with the Jackson candle method

The Jackson Candle method is an old way to measure turbidity in Jackson Turbidity Units (JTU). A tall, clear tube with measurement marks is placed over a lit candle. Water is slowly poured into the tube until the candle’s flame is no longer visible when looking from the top. The height of the water at that point is read using the scale on the tube, giving the turbidity in JTU. The higher the turbidity, the quicker the flame disappears from view. This method is mostly used for very cloudy water and is now less common due to newer tools.