The tank will hold approximately 600 gallons;

squared(radius)*PI*height =
16*3.1415*2==100.52 cubic feet =
* 7.48 gallons per cubic foot =
751 gallons, overflowing

Can anyone give me some suggestions on how I should clean and condition the
new galvanized metal?

Read both links; they say different things. Look for "galvanized".

http://www.wetwebmedia.com/PondSubWe...contpdsart.htm
http://www.wetwebmedia.com/tkstdfaq.htm

You could line the thing with the standard pond liner,
which will be black, and will solve your painting problem also.

(Look for directions on the net regarding pond liners, pleating,
and so forth, but really--not rocket science).

As for your plumbing, if you don't put a bottom drain in, you'll
wish you did. You may consider having the bottom drain connect
through underground conduit to some second small tank. As you
put more water in your pond, gravity will naturally push the
water in your pond to the second tank. From their, you will
pump water in the second tank to the pond, ad nauseum.

Water on the bottom of the pond is lowest in oxygen, so you'll
be oxygenating your pond simply by bringing this low oxygen
water to the surface, where it pick up more air by exchange.

Structured right, this second tank can be made to pick up a
lot of your pond detritus. Vacuuming the second tank will be
a lot easier than vacuuming the main pond...

C//