Particle system looks different on iOS 6 and ios7 - ios

Question

I have a couple of particle systems on my app that I checked originally on an iPad 3 with ios7. The particles looked and behaved like I expected them, but when I test on an iPad2 with ios6. The particles are displaced up and are smaller. I have a subclass for the particles. Here's the code for one of my particle systems. I was wandering if the CGREctMake is positioning the particle in a different area on a non retina display, but that doesn't happen when I position other things on the display.
Code to call the particles.
- (void)ShowSteamEffect
{
//Create view for Steam particle effect.
CGRect SteamFrame = CGRectMake(790, 380, 100, 100);
//Show Steam effect
ShowSteam = [[SteamEffect alloc]initWithFrame:SteamFrame];
ShowSteam.hidden = NO;
[self.view insertSubview:ShowSteam aboveSubview:imgComputerLights];
}
Steam subclass.
#import "SteamEffect.h"
#implementation SteamEffect
{
CAEmitterLayer* SteamEmitter;
}
- (id)initWithFrame:(CGRect)frame
{
self = [super initWithFrame:frame];
if (self) {
// Initialization code
SteamEmitter = (CAEmitterLayer*) self.layer;
//SteamEmitter.emitterPosition= CGPointMake(0, 0);
//SteamEmitter.emitterSize = CGSizeMake(10,10);
CAEmitterCell* Steam = [CAEmitterCell emitterCell];
Steam.birthRate = 50;
Steam.spin = .6;
Steam.lifetime = 1.7;
Steam.alphaRange = 0.2;
Steam.alphaSpeed = 0.2;
Steam.contents = (id)[[UIImage imageNamed:#"Steam1.png"]CGImage];
Steam.velocity = 30;
Steam.velocityRange = 50;
Steam.emissionLongitude = -60;
Steam.emissionRange = M_1_PI;
Steam.scale = .2;
Steam.scaleSpeed = .5;
Steam.yAcceleration = -200;
SteamEmitter.renderMode = kCAEmitterLayerBackToFront;
SteamEmitter.emitterShape = kCAEmitterLayerCircle;
SteamEmitter.emitterCells = #[Steam];
}
return self;
}
-(void)didMoveToSuperview
{
[super didMoveToSuperview];
if (self.superview==nil) return;
[self performSelector:#selector(disableEmitterCell) withObject:nil afterDelay:0.5];
}
-(void)disableEmitterCell
{
[SteamEmitter setValue:#0 forKeyPath:#"birthRate"];
}
+ (Class) layerClass
{
//tell UIView to use the CAEmitterLayer root class
return [CAEmitterLayer class];
}
- (void) setEmitterPosition:(CGPoint)pos
{
SteamEmitter.emitterPosition = pos;
}
- (void) toggleOn:(bool)on
{
//SteamEmitter.birthRate = on? 300 : 0;
}