How freeing memory during viewController transition - ios

Question

I explain my problem.
I just made a game with 3 views.
the game presentation with a playbutton
the game scene
the game over scene with a button to play again or go back to the presentation scene.
My problem is when there is a transition between two scenes, the active memory will be 30MB more and each scene transition will increase the active memory about 30MB and will never decrease.
How can I fix it and release memory ?
Thank you all
My transition code :
// Transition in presentationViewController file
func transition(sender:UIButton!)
{
println("transition")
let secondViewController = self.storyboard?.instantiateViewControllerWithIdentifier("GameViewController") as UIViewController
let window = UIApplication.sharedApplication().windows[0] as UIWindow
UIView.transitionFromView(
window.rootViewController!.view,
toView: secondViewController.view,
duration: 0.65,
options: .TransitionCrossDissolve,
completion: {
finished in window.rootViewController = secondViewController
})
}
// transition in GameScene file
func removeCountDownTimerView()
{
defaults.setInteger(balloonDestroyed, forKey: "score")
let storyboard = UIStoryboard(name: "Main", bundle: nil)
let gameOverScene: UIViewController = storyboard.instantiateViewControllerWithIdentifier("GameOverViewController") as UIViewController
let vc = self.view?.window?.rootViewController
vc?.presentViewController(gameOverScene, animated: true, completion: nil)
}
// transition in gameOverViewController file
func transition(sender:UIButton!)
{
println("play transition")
let secondViewController = self.storyboard?.instantiateViewControllerWithIdentifier("GameViewController") as UIViewController
let window = UIApplication.sharedApplication().windows[0] as UIWindow
UIView.transitionFromView(
window.rootViewController!.view,
toView: secondViewController.view,
duration: 0.65,
options: .TransitionCrossDissolve,
completion: {
finished in window.rootViewController = secondViewController
})
}

Answer 1

instantiateViewControllerWithIdentifier("GameViewController") as UIViewController
This code is creating new ViewController each time user press the button. I advise you to use singletone pattern for this.
private let _SomeManagerSharedInstance = GameViewController()
class GameOverViewController {
class var sharedInstance: GameOverViewController {
return _GameOverViewController
}
You can also create a private class method for instantiating the View Controller from storyboard.