I'm installing a Chicago Faucet 2-handle shower valve in my new shower. It's brass, and now I need to run a supply line up to the shower head. The shower head is an old Speakman Model #1 and the angled pipe feeding it and passing through the tiled wall is chrome plated brass. Will there be a problem using galvanized iron pipe due to dissimilar metals in long-term contact? With brass at the shower head and brass at the shower valve I hate to mess things up with iron pipe in between. But would that be a problem?