On Sat, 25 May 2013 10:46:58 -0400, gfretwell wrote:

I doubt it really makes much difference.

I tried calling Aladdin Equipment (941-371-3732) today (http://www.aladdin1950.com)
to ask what they make their kits out of, since they use trade sizes in their kit
descriptions; but they're not open on Saturdays.

Swimming pool water is about as benign a fluid as you can find.

I was thinking sunlight + water + chlorine + acid was the environment.
Note: Sunlight might be eliminated once installed though.

This is a reference
http://www.grainger.com/tps/pumps_ch...patibility.pdf

Wow! Thanks. Comprehensive. A keeper! Mostly for metals though.
They list Buna-N (aka Nitrile) & Viton, & maybe Silicone; but not EPDM, nor Kalrez.
Note: They list "Silicon" in the rubber section, so maybe that's a typo?

Googling for o-ring materials, it seems the material choices go in this order:
a. First see if Buna-N (Nitrile) will work (because it's the cheapest solution).
b. If that won't work, use Silicone,
c. If that won't work, use Viton (Fluoro-elastomer),
d. If that won't work, use EPDM,
e. If that won't work, use Kalrez (perfluoro-elastomer).
REF: http://www.metrogasket.com/o-rings/m...tion_guide.htm