Benign Vanilla wrote:


"Derek Broughton" wrote in message
...
snip
The old-timers here will remember that, at the time I started into
ponding,
sometime in the mid-90s, one of the hottest debates was over the use of
pond-safe EPDM and EPDM roofing liner. Firestone, the major manufacturer
of both, insisted that the roofing liner was not fish-safe, but many
people
used it without trouble. I know of one DIY study that claimed it killed
test fish, but I also know of dozens of respected ponders who never had a
problem.
snip

The key variable here is that in some areas, roofing liner can be treated
for fungus, mildew, etc. and those chemicals could be harmful to fish. My
EPDM was purchased from a pond store, and it says Firestone on it. So I
guess my area does not have these "mythical" chemicals.

That was part of the discussion, but while a number of _roofers_ claimed it
was treated with fungicides, nobody connected with Firestone ever said
that. So, yes, they seem to be mythical. But I still wouldn't risk a
hundred dollar koi in a pond made with roofing liner. The stuff you got
was almost certainly pond-grade, though. Firestone does sell pond-grade
epdm, and it doesn't come from the same supply as roofing-grade epdm - but
whether there's any chemical difference, nobody really knows.
--
derek