Hi @Bondra
The normal WP WYSIWYG is not availing in ACF due to limitations within the repeater field.
If you are using the WYSIWYG field OUTSIDE of a repeater field / flexible content field, you can install an add-on I created that uses the WP WYSIWYG and offers the native visual / text tabs:
http://www.advancedcustomfields.com/add-ons/wordpress-wysiwyg/
Thanks
E