Hi,

I play someone in a tournament, he was on vacation, then he came out of vacation, his time went down to only a few minutes and now his clock is standing at 12 hours again.

How can this be?

http://support.chess.com/Knowledgebase/Article/View/26/0/how-does-vacation-work--how-much-time-do-i-get

"All vacation times will be consume a minimum of 24 hours."

What is not written is the unused part of the 24 hours is added to the game clock. Just pretend he is still on vacation and it is the same.

ok, thanks, that explains it.