How can I use both of these in the same UIView correctly?

I have one custom subclassed CALayer in which I draw a pattern within drawInContext

I have a another in which I set an overlay PNG image as the contents.

I have a third which is just a background.

How do I overlay all 3 of these items?

[self.layer addSublayer:bottomLayer];    // this line is the problem

[squaresLayer drawInContext:viewContext];
[self.layer addSublayer:imgLayer];

The other 2 by themselves draw correctly if I do them in that order. No matter where I try and put bottomLayer, it always prevents squaresLayer from drawing. The reason I need 3 layers is I intend to animate the colors in the background and custom layers. The top layer is just a graphical overlay.