Akop “Jack” Torosian, owner of No Limit Super Gym in Los Angeles and Miami, had a grand re-opening over the weekend at his Hollywood location after some remodeling ... things started to get heated when he allegedly found out someone was selling juice in the gym without his permission.

He's heard complaining about a "Mexican" selling their product at his place, telling someone to "get him the f*** out of here," adding "this is not a Mexican hangout."

Jack, who refers to his gym as a "sanctuary" online -- and posts videos of himself smoking, while lifting, while getting a haircut -- has since apologized, saying the video was out of context ... though it's hard to explain the racist phrasing used.

He's claiming his own staff had been taking advantage of him ... while being away in Miami, he says his employees opened up a juice bar and brought outside vendors to help -- something he claims wasn't approved.