II. EXTERNAL SIGHT TUBES

The procedures for accurately measuring milk volume in a milk tank with external gauges are:

1. Check sight tube hoses (top and bottom) and clear them of water, milk, kinks or other obstructions.
2. Slowly allow milk to enter the sight tube, this will minimize foam formation. Open the tank valve partially until the milk has stabilized in the tube. Once the milk has stabilized, fully open the valve.
3. Align the gauge slide with the top of the milk in the sight tube.
4. Read the gauge to the closest graduation mark. When the milk line falls exactly between two marks read to the nearest even number.
5. Record the reading on the weight ticket then discard the milk in the sight tube. Close the tank valve before discarding sight tube milk.

Several factors can change the accuracy of the gauge.

☐ Discoloration of the tube which obscures the reading ☐ Foam in the tube ☐ Replacing the tube with a hose that has a smaller or larger interior diameter ☐ Water in gauge tube hoses ☐ A leaking connection on the hose between tank valve and gauge tube ☐ A dirty sight tube due to improper cleaning by CIP system and/or producer taking readings between milk pickups.

III. FACTORS AFFECTING BULK TANK MEASUREMENTS

The farm bulk tank and its calibration are the responsibility of the producer and plant they supply. However, there are conditions that the hauler should be aware of that could contribute to inaccurate weight problems

1. The tank is incorrectly calibrated
2. Errors in the weight conversion chart
3. Bulk tank is out of level
4. Heaving, cracking, or settling of milk house floor causing the bulk tank to shift
5. Improper footings under the tank legs
6. A weaving distortion of the measuring stick, bracket, or seat
7. Measuring rod gauge points don't line up properly

If you notice any discrepancies, contact the producer.

CORRECT AGITATION TIME

Proper agitation is essential in obtaining a sample that is representative of the milk in the tank. With inadequate agitation, samples taken from the top of the tank contain more bacteria, somatic cells, and milk fat than samples taken low in the tank.

As a general rule, agitate for five minutes. For tanks of 1500 gallons or larger, agitate for ten minutes. Silos may require additional agitation time for a proper sample. Check with the producer or find the tank plate with the Model number may have the proper agitation time. If the agitator is running when you arrive, start timing then.

TEMPERATURE

The temperature of the milk must be measured at each pickup. The recommended thermometer should have a stainless-steel stem, an unbreakable plastic window, an external adjustment for calibration and an accuracy of ± 1circC (±2°F).