Tank was installed in May 1992, just over 20 years ago. Tank is now leaking from underneath it's base, I'm assuming that that the bladder inside has sprung a leak and leaking through the steel tank at the bottom.. . My question... The only solution is to replace the tank?.
Thanks Ken

Actually, it's the tank itself that is leaking. Unless it is leaking from the T fitting, the tank is bad. Twenty years is a pretty good lifespan for a pressure tank.

I suppose it could be dripping a little condensation, with hot temps and high humidity combined with fairly cold water in the tank, but that's a longshot. And it would have done that for the past twenty years.

Yes, at this point, the best solution is to replace the tank.