Sealer for a steel water tank

[TimRB]

We have a 10,000 gallon steel tank that is badly in need of interior refinishing.  Any idea of what would be good for that?  The paint/whatever needs to be something that can be applied with brush or roller, and not toxic to breathe while inside the tank.  Cheap is also good.  

Tim

[Kbeitz]

We had a 1000 gal spray tank on the farm that went bad. Coated the inside with fibered roofing tar. Worked great.

[florida]

TimBR
One of my brothers is an engineer/tank expert. Took care of hundreds of tanks of all kinds at a paper mill before he retired. I'll ask him but he'll want to know what goingin it.

[TimRB]

 I'll ask him but he'll want to know what goingin it.

Hmmm--that WOULD be relevant information, wouldn't it? 
Household water
And THANKS very much for checking this out!
Tim

[Kbeitz]

Drinking water then I would say fiber glass it... You would need to breathing protection.

[florida]

TimRB
He says, "If it's for portable water it isn't easy and is not a job for amateurs. Tough, labor intensive and very expensive. Surface prep and substrate condition are paramount. We would start with a white metal blast with the workers using supplied breathing air, booties and gloves to prevent fingerprint oil contamination.We ran dehumidifers at all times. 3 coats of primer with 100 percent holiday testing between coats. Coating would be epoxy or vinyl ester. Fiberglass or rubber could be alternatives. The most expensive tank in the world is a free one that needs to be sealed."

He added that obviously you need an access hole or even 2  and lots of clean breathing air.  The cost to reseal might be more than the cost of a  new plastic tank. He built and maintained huge tanks for everything from potable water to waste oil and black liquor. 

[Kbeitz]

Maybe a plastic bladder if you could find one...

[moodnacreek]

Have patched small fuel tanks by lite sand blasting or needle scaling and coating with POR and fiber glass cloth. [rusty steel]  This method can last a long time.