Form validation returning FALSE

$this->CI =& get_instance();
in the constructor and many of the functions return $this.

The makes the return rather large, and redundant and circular.

Actually, it's not really large. The return is a reference which (more or less) uses only enough memory to hold a memory address. The debugger is confused and makes it look huge. It's only circular in that it appears to be copied. It's kind of like when you have two mirrors facing each other. There aren't really thousands of rooms inside each other, merely reflections of reflections going on forever.