Google analytics vs Piwik traffic

Hi everyone, I have little problem. I start to using piwik for traffic analytic. I`am using it on my joomla page . First I paste code on the end of my template page, but, traffic was smaller about 300% than google analytic. On Piwik was about 100 visitors and on google analytic was 350 visitors. After that I try with 301 Moved Permanently but difference was the same about 200%-300%
Best regards