I just iclude the code of canonical tag, and my errors of duplicate titles and pages was reduced dramatically)
I'm a not programmer and if somebody can make this code better will be great.( I found it in internet and make small changes)
In /includes/templates/YOUR TEMPLATE/common in html_header.php

direct after <title><?php echo META_TAG_TITLE; ?></title> need to add:
PHP Code:
<link rel="canonical" href="<?php
$original_url = HTTP_SERVER . $_SERVER['REQUEST_URI'];
$split_url = explode('?', $original_url);
$no_querystring_url = $split_url[0];
echo $no_querystring_url; ?>" />
also you need to exclude in SSU settings (admin part) "Set Query Key's Exclude List" the " max_display "

you can check how the canonical work in this links of my site:
http://www.usim.co.il/nokia?max_disp...ort=20a&page=3
and
http://www.usim.co.il/nokia
Thanks