ADInterstitialAd is causing memory problems

I am developing an iPhone / iPad using the Sprite Kit and in between each round I load an interstitial ad.

The interstitial is loaded on GameViewController

top and sits on top skview

. I am using a series of watchers to trigger and cancel advertisements and it all works fine.

However, I noticed some serious memory issues and after 4 or 5 rounds the application will crash. It appears to be directly linked to the iAd interstitial site. I have attached my code and you can see that I am freeing objects, but the memory folder printing does not seem to crash. I am also using ARC.

Does anyone know what might be causing this problem? I read here: iAd and AdMob Heavy on Memory that the view webkit

seems to support its contents. I need to find a way to fix this, my code for mine GameViewController

looks like this:

#pragma mark - GAME LOAD
-(void)loadStartScreen{
    _theView = (SKView *) self.view;
    _theView.showsFPS = YES;
    _theView.showsNodeCount = YES;
    //Sprite Kit applies additional optimizations to improve rendering performance
    _theView.ignoresSiblingOrder = YES;

    // Create and configure the scene.
    _theScene = [MainMenuScene sceneWithSize:_theView.bounds.size];
    _theScene.scaleMode = SKSceneScaleModeAspectFill;
    _theScene.backgroundColor = [UIColor grayColor];

    // Present the scene
    [_theView presentScene:_theScene];

    // setup observer
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(requestFullScreenAd) name:@"requestAdvert" object:nil];
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(showFullScreenAd) name:@"showAdvert" object:nil];
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(cancelAdverts) name:@"cancelAdvert" object:nil];
}

#pragma mark - ADVERT CREATION AND SUPPORT
-(void)requestFullScreenAd {
    // run the process on the main thread in a background queue
    dispatch_async(bGQueue, ^{
        if (_requestingAd == NO) {
            _interstitial = [[ADInterstitialAd alloc]init];
            _interstitial.delegate = self;
            self.interstitialPresentationPolicy = ADInterstitialPresentationPolicyManual;
            NSLog(@"Ad Request");
            _requestingAd = YES;
        }
    });
}

-(void)showFullScreenAd{
    if (_adLoaded) {
        CGRect interstitialFrame = self.view.bounds;
        interstitialFrame.origin = CGPointMake(0, 0);
        _adView = [[UIView alloc] initWithFrame:interstitialFrame];
        [self.view addSubview:_adView];

        [_interstitial presentInView:_adView];

        _button = [UIButton buttonWithType:UIButtonTypeCustom];
        [_button addTarget:self action:@selector(closeAd:) forControlEvents:UIControlEventTouchDown];
        _button.backgroundColor = [UIColor clearColor];
        [_button setBackgroundImage:[UIImage imageNamed:kCloseAd] forState:UIControlStateNormal];
        _button.frame = CGRectMake(10, 10, 40, 40);
        _button.alpha = 0.75;
        [_adView insertSubview:_button aboveSubview:_adView];

        [UIView beginAnimations:@"animateAdBannerOn" context:nil];
        [UIView setAnimationDuration:1];
        [_adView setAlpha:1];
        [UIView commitAnimations];
    }
}

-(void)closeAd:(id)sender {
    [UIView beginAnimations:@"animateAdBannerOff" context:nil];
    [UIView setAnimationDuration:1];
    [_adView setAlpha:0];
    [UIView commitAnimations];

    _adView=nil;
    _requestingAd = NO;
    _button = nil;
    _interstitial.delegate = nil;
    _interstitial = nil;

    // notification for ad complete
    [[NSNotificationCenter defaultCenter] postNotificationName:@"adClosed" object:nil]; 
}

-(void)cancelAdverts{
    [_interstitial cancelAction];
    _adView=nil;
    _requestingAd = NO;
    _button = nil;
    _interstitial.delegate = nil;
    _interstitial = nil;
}

#pragma mark - IAD DELEGATE
-(void)interstitialAd:(ADInterstitialAd *)interstitialAd didFailWithError:(NSError *)error {
    [_interstitial cancelAction];
    _adView=nil;
    _requestingAd = NO;
    _button = nil;
    _interstitial.delegate = nil;
    _interstitial = nil;
    NSLog(@"Ad didFailWithERROR");
    NSLog(@"%@", error);

    // request another advert if it failed
    //[self requestFullScreenAd];
}

-(void)interstitialAdDidLoad:(ADInterstitialAd *)interstitialAd {
    if (interstitialAd.loaded) {
        _adLoaded = YES;
        [[NSNotificationCenter defaultCenter]postNotificationName:@"adLoaded" object:nil];
    }
    NSLog(@"Ad DidLOAD");
}

-(void)interstitialAdDidUnload:(ADInterstitialAd *)interstitialAd {
    [self closeAd:nil];
    NSLog(@"Ad DidUNLOAD");
}

-(void)interstitialAdActionDidFinish:(ADInterstitialAd *)interstitialAd {
    [self closeAd:nil];
    NSLog(@"Ad DidFINISH");
}

      

        
        
        
      

    

Then on my level the complete SKScene:

#pragma mark - SCENE APPEARS
-(void)didMoveToView:(SKView *)view {
    // request an advert if advert removal is not purchased
    if (![[[UserDetails sharedManager]iapAdsRemoved]boolValue]) {
        // send request ad notification
        [[NSNotificationCenter defaultCenter]postNotificationName:@"requestAdvert" object:nil];
        // look for add loaded notification
        [[NSNotificationCenter defaultCenter]addObserver:self selector:@selector(adLoaded) name:@"adLoaded" object:nil];
        // look for add completed
        [[NSNotificationCenter defaultCenter]addObserver:self selector:@selector(adShowCompleted) name:@"adClosed" object:nil];
    }

    // setup UI
    [self createUI];

    if (![[UnlockController sharedManager]allunlocksOpen]) {
        // check all unlocks
        [[UnlockController sharedManager]checkUnlocks:[[UserDetails sharedManager]userTotalScore]+[[UserDetails sharedManager]userLevelScore]];

        // get the next unlock
        [self getNextUnlockScore];

        // set bar with correct increment
        [unlockBar setBarValues:[[UserDetails sharedManager]userTotalScore]+[[UserDetails sharedManager]userLevelScore] increment:[[UserDetails sharedManager]userTotalScore] nextObject:nextScore];
    }
    else{
        [self allUnlocksOpen];
    }

    // pre add button
    preAdButtonPress = 3;

    // variables
    startCount = 0;
    unlockItemsCount = 0;
    allUnlocks = [[UnlockController sharedManager]finalUnlockOpen];

    // start unlocks sequence
    [self performSelector:@selector(runRewards) withObject:nil afterDelay:1.0];
}

-(void)willMoveFromView:(SKView *)view{
    // cancel any adverts
    [[NSNotificationCenter defaultCenter]postNotificationName:@"cancelAdvert" object:nil];
    // remove observers
    [[NSNotificationCenter defaultCenter]removeObserver:@"adClosed"];
    [[NSNotificationCenter defaultCenter]removeObserver:@"adLoaded"];
}