Oxygen Tank Stainless Steel or Welders Steel Oxygen Tank

I am making batches of beer 25 - 35 gallon.  The red oxygen tanks are not lasting long enough for me.  I am considering purchasing an M80 welders steel oxygen tank with a CGA540 regulator  0-4LPM.  Is there any reason to be concerned about contaminating the beer by using a welders steel oxygen tank instead of a stainless steel medical grade oxygen tank?

Don’t see why - CO2 doesn’t come in stainless tanks. That must be frickin expensive too.

I’ve been using a welder’s O2 tank for years.
RDWHAHB