Air in plumbing lines

I just had a new fresh water holding tank installed on my home system. Each time I turn the water on (hot or cold) I get air through the system. I have drained the new tank and refilled and bled the air from it. I have a shutoff valve just after the tank. I shut it off and checked the line presure to see if there was a drop in the presure, there was none. I'm getting air from somewhere in the system but I don't know how or where. Any advise on this problem would be of great help.

The only way I have ever gotten water out of lines is to open all the faucets, flush toilets, etc. for about 5 mintues. Don't close off any supply lines or drain tanks. That typically only induces air into the system.

Anyway, the "all open" method has always done the trick for me.