Captive air tank

I have a new-looking 90-gallon captive air tank that I used for only a month way back in 1982. It has been stored since then (filled with water) , but now I'd like to put it back into service. New ones are EXPENSIVE! Any chance it's still good? How would I test it before hooking it up to my new system? Do the bladders last that long before deteriorating? If it's not good , can I replace the bladder? Or is it just not worth it? I'd appreciate any one of my questions answered by someone in the know. Thanks! Dorothy

Most likely it is better than anything you can purchase today. Just air up the bladder to 40 PSI. If it still has the same pressure in a couple of days, it will probably be fine. However, now there are things like a Cycle Stop Valve which will let you use a 4.4 gallon tank and do a better job than a big tank.