11.4.2. The milk volume measurement required by subparagraph 2 of the first paragraph of section 11.4.1 must be taken with a measuring stick or gauge tube.
If the tank is equipped with a measuring stick, the tester must(1) ensure that the stick is dry, clean and upright;
(2) lower the gauge into the bulk tank when the milk in the tank is still until it is seated fully in its support;
(3) remove the stick at once and read and record the highest graduation mark closest to the milk line; and
(4) repeat the operation until 2 identical readings are obtained.
If the tank is equipped with a gauge tube, the tester must(1) ensure that the tube is clean and that the graduation marks are easy to read;
(2) open the valve at the bottom of the tube to allow the milk to flow in slowly; and
(3) read and record the higher graduation mark at the bottom of the meniscus closest to the milk line.