public function removeFilter($filterHash)
    {
        // Make lower case
        $filterHash = strtolower($filterHash);

        // Remove this filter if it has been defined
        if (array_key_exists($filterHash, $this->options['filters'])) {
            unset($this->options['filters'][$filterHash]);
        }

        unset($filterHash);

        return $this;
    }