Faa -- locally they HAMMER me for hydro's. THey get me for a Hydro. Cleaning, Vip, and Fill I beleive last time it was $80.00 for my Steel 100
My Shop charged $35 for air and $65 for nitrox hydro (oxygen service) because there is a minimum 1 hour labor involved in tumbling a tank and rebuilding/clearning the valve. Tanks SUCK-