I just got a call back from a very nice rep from Vertex. The production date codes read as follows:
First character, ALPHA, corresponds to the Month: A=1=January, B=2=February, C=3=March, etc.
Second two characters, NUMERIC, is the day of said month. 01-31.
Fourth character, NUMERIC, last digit of Year.
Characters 5-7 are not important unless you have an issue. It is simply the ID of the tank in which it was produced.
Character 8 is the manufacturing plant. It should always be "D" since Dupo, IL is the only plant they use to manufacture the product.
Example: "F1900004D" Would be June19, 2020.
