Right you are, David.

Chlorine can infiltrate the crystal structure of most steels, which can
result in stress corrosion cracking. It is more pronounced at higher
temperatures as the natural vibration of the metal atoms (causing the size
change we know as "thermal expansion") means there's more space between the
atoms for the chlorine to penetrate the crystal lattice.

--

Ray Barkalow - First Rays Orchids - www.firstrays.com
Plants, Supplies, Books, Artwork, and Lots of Free Info!

.. . . . . . . . . . .
"DKafkewitz" wrote in message
...
A note of caution about using bleach to control algae. My greenhouse has a
gas
heater. The instructions for the heater warn against the use of chlorine
bleaches when the heater is in use. The fumes from the bleach can react
with
the metal of the heat exchanger at the high temperatures that exist when
the
heater is operating. This can, according the the instructions, greatly
shorten
the life of the heat exchanger.

David