Charset en gtmetrix

[mblascog]

Hi,
It's the first time I'm doing SEO in a web. Checking it with GTmetrix tool, it suggest to avoid a character set in the meta tag. For this I've remove

Código PHP:

<meta http-equiv="content-type" content="text/html; charset=UTF-8"/>
 

from my php files, and I've added

Código Apache:

AddDefaultCharset UTF-8
 

into my htaccess file

If I test my web with this modification in localhost it's perfect. But when I test from the domain, the charset is bad.

Any idea what else I have to change to the external server?

Thanks