I have three kids that are all playing SK. All three have their own accounts. However, for some reason, it seems two of them have a shared energy pool.
Both had 100 mist energy this morning. The first played a few floors and logged out. Then, when the other logged in, he only had 62 mist energy... the same amount the first one had when he logged out. They're sharing a computer, but that shouldn't matter if they have their own accounts, right?
As an anti-farming measure, free accounts share a mist pool when playing on the same computer. If you purchase any amount of CE on an account, it becomes exempt and gets an independent mist pool for life.
There are 2 way to handle this. They can either all play from different computers (if you have enough)... or you can buy the $3 CE pack for at least 2 of the accounts, so they no longer have to share a common mist pool.