It does.
As does you rock and substrate.....or in your case the old substrate.
But adding new media won't help.Eventually the new media will get seeded with bacteria,but it will not help it grow faster or more of it quicker.....no more then adding more new substrate will.
On a side note,do not change the old media...make sure it stays clean (no excess waste) with each PWC but keep using it until the cycle is complete again.