The zinc that is used in the galvanization process is fairly insoluble at
the normal pH of water, and therefore should last a long time. If the zinc
is dissolved, it can be harmful to the fish when the levels get high. If
the bottom is not kept clean, layers of rotting leaves will become acidic,
the galvanization will be removed and the metal will corrode. Painting will
help to protect the galvanization. Many of the farm supply places that
supply the galvanized tanks have similar polyethylene tanks, and they will
not corrode. The polyethylene tanks will embrittle in sunlight (UV), so it
is a good idea to provide the stack wall you discuss, and water absorbs some
of the UV. They do make paints for plastics now so that you can make it any
color you want. At least until the green algae covers it.
--
RichToyBox
http://www.geocities.com/richtoybox/pondintro.html

"Sue Solomon" wrote in message
news:qH5se.88307$yV4.68870@okepread03...
Hi All
I'm about to install a new pond in my front yard. Due to several
factors
(limited space, invasive tree roots nearby, neighbor's dogs cavorting in
my
existing plastic pond), I've decided to sink an 8' round, 2' deep
galvanized
steel stock tank about 12" into the ground for my pond. I plan to put a 2"
base of sand under the tank to level it. I will then cover the protruding
sides with stackable concrete blocks and cement a top ring of pavers in
place to finish it. I was going to paint the inside black, but if the tank
has to be sandblasted first, forget it. The tank will hold approximately
600
gallons; I'm planning to add goldfish, filter, fountain and a couple of
small water lilies to it. I plan to drill several holes in the tank side
for
fountain and filter feeds before burying it, and will eventually install a
small biological filter next to it. We live in Southern California, so I
don't have to worry about the ground freezing.

Can anyone give me some suggestions on how I should clean and condition
the
new galvanized metal? Anything else I need to do? I got the idea from my
Midwestern upbringing - both my father and grandfather kept goldfish in
their cattle stock tanks to control mosquito larvae, and they eventually
got
pretty big. I always loved watching the goldfish swimming so peacefully.

Thanks in advance for your help --
Sue in SoCal