Talk:Game Updates/@comment-11452756-20131025022059/@comment-5786363-20131025122743

It does - in order to purchase 1000 Magic you need to have 500 or less Stored up in your Magic Pool.

While it may be immediately cast, you still need the 'storage space' for it to cast through. I'm confirmed this multiple times, twice now I've decided to purchase 1000 magic, and I always do it at the end of the day, after I empty my pool the 1000 Magic purchase reappears.