sharann is right. Vit K and Potassium are NOT the same thing.

the letter "K" is the chemical element symbol for Potassium (just like Fe=Iron, Na=Sodium, etc) -- so things that are a potassium supplement may use a "K" in their name, but this is definitely not the same thing as Vitamin K.

the link posted seems to call potassium "vitamin K" - but this would be incorrect and misleading to couple "vitamin" with "K" and mean potassium.
In many texts, potassium might be referred to as K (see Merck link below), just as Ca might be used to reference calcium, or Fe for iron.

here is a link to the Merck Manual about Vitamin K:
Vitamin K

here is a link to the Merck Manual about Potassium:
Potassium