[RE-wrenches] Hot water tank liner recommendations?

[David Palumbo]

Wrenches,

Does anyone have a recommendation for a waterproof material to line a 950
gallon hot water storage tank? This insulated storage tank will have heat
exchange coils from a wood fired Tarm boiler as well as from SHW collectors.
The liner must be able to withstand temperatures of 180 degrees F.

We have had recommendations that include EDPM roofing membrane, and pond
liner material http://www.firestonesp.com/pondgard.asp?sub=b1a and
http://www.firestonebpe.com/lining/tech_data/tech_guidelines/_down/_en/T and
http://www.firestonebpe.com/lining/tech_data/tech_guidelines/_down/_en/T

Also, there is a concern that these tank liners have leaked in the past
because the bottom of the tank liner was eventually penetrated due to poor
protection from the stress of having the copper heat exchanger coils sitting
on it. I'm wondering if closed cell blue(or pink) board insulation would be
a good choice for this duty. Will it hold up over the years at temps up to
180F? As an alternative we could mill up some local Hemlock wood to separate
the coils from the liner. Hemlock has been used for years to build spring
boxes out of, the reputation being "that as long as the wood stays wet it
will last for decades".

And, is there a water treatment product that we should add to the storage
tank that will help protect the liner from breaking down over the years?

Thanks for your time,

Dave Palumbo
Independent Power LLC