Objective c - Memory Usage Keeps Increasing - Iphone App - ios

Question

I have a recursive loop using NSTimer that runs every two seconds and calls a function that calls the setupPhpCall function:
There are 3 NSTimers that run and always hits the setupPhpCall function,
could this be where the memory leakage is happening?
-(NSString*)setupPhpCall:(NSString*)requestString :(NSString*)sciptPage{
NSData *myRequestData = [NSData dataWithBytes: [requestString UTF8String] length: [requestString length]];
// Create your request string with parameter name as defined in PHP file
NSMutableURLRequest *request = [[NSMutableURLRequest alloc] initWithURL: [NSURL URLWithString: [NSString stringWithFormat: #"http://www.xxxx.co.uk/%#", sciptPage]]];
// set Request Type
[request setHTTPMethod: #"POST"];
// Set content-type
[request setValue:#"application/x-www-form-urlencoded" forHTTPHeaderField:#"content-type"];
// Set Request Body
[request setHTTPBody: myRequestData];
// Now send a request and get Response
NSHTTPURLResponse* urlResponse = nil;
NSError *error = [[NSError alloc] init];
NSData *returnData = [NSURLConnection sendSynchronousRequest: request returningResponse:&urlResponse error: &error];
// Log Response
NSString *response = [[NSString alloc] initWithBytes:[returnData bytes] length:[returnData length] encoding:NSUTF8StringEncoding];
NSLog(#"%#",response);
return response;
}
This is the recursive method thats called using NSTimer:
-(void)recurseForumActivity:(NSTimer *)timer{
dispatch_queue_t concurrentQueue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0);
dispatch_async(concurrentQueue, ^{
NSString *myRequestString = [NSString stringWithFormat:#"lastDate=%#&threadTitle=%#&threadCountry=%#&threadCategory=%#&threadSubCategory=%#&getData=0",lastDateForumActivity,searchThreadTitle, searchThreadCountry, searchThreadCategory, searchThreadSubCategory];
NSString *response = [self setupPhpCall:myRequestString :#"xxx.php"];
dispatch_async(dispatch_get_main_queue(), ^{
if(response.length > 0 && ![response isEqualToString:#"[]"]){
labelNewForumThreads.text = [NSString stringWithFormat:#"%# new threads...", response];
if(imageviewForumAlert == NULL){
UIImage *image = [UIImage imageNamed:#"alert.png"];
imageviewForumAlert = [UIImageView new];
[viewNav1 addSubview:imageviewForumAlert];
imageviewForumAlert.translatesAutoresizingMaskIntoConstraints = NO;
imageviewForumAlert.image = image;
NSDictionary *viewsDictionary = #{#"imageviewForumAlert":imageviewForumAlert};
NSArray *constraint_H = [NSLayoutConstraint constraintsWithVisualFormat:#"V:|-19-[imageviewForumAlert(12)]-19-|"
options:0
metrics:nil
views:viewsDictionary];
NSArray *constraint_V = [NSLayoutConstraint constraintsWithVisualFormat:#"H:|-19-[imageviewForumAlert(12)]-19-|"
options:0
metrics:nil
views:viewsDictionary];
[self.view addConstraints:constraint_H];
[self.view addConstraints:constraint_V];
}else{
imageviewForumAlert.hidden = NO;
}
/**NSDictionary *dic = [response JSONValue];
if((NSNull*)dic != [NSNull null]){
labelNewForumThreads.text = [NSString stringWithFormat:#"%d new threads...", dic.count];
}**/
}else{
imageviewForumAlert.hidden = YES;
labelNewForumThreads.text = [NSString stringWithFormat:#"%d new threads...", 0];
}
/**else{
labelNewForumThreads.text = [NSString stringWithFormat:#"%d new threads...", 0];
}**/
});
});
}
EDIT
In the console i get this error after i have left the app to run for more than one hour:
Communications error: <OS_xpc_error: <error: 0x361c0614> { count = 1, contents =
"XPCErrorDescription" => <string: 0x361c086c> { length = 22, contents = "Connection interrupted" }
}>
i have Allocation tool running aswel
this is the screenshot of allocation tool when the app crashes
EDIT
EDIT
I have also noticed when starting Instrument Allocations tool my memory usage rapidly shots up quicker, why is this?