Rainwater has a lot of other problems, too. Like, it's usually pretty soft,
lacking any carbonates to buffer your pH and *other* minerals that help the
fish adjust to life in captivity. The pH can also be questionable in
general: in the summer, if the rain comes in off the Gulf of Mexico, it's
usually OK, pretty close to neutral. But if the rain comes *across* FL -
over the phosphate mines - the pH can be in the mid 4's. Get a couple
inches of that in your pond, and if you're not properly buffered, you're
looking at a crash. It's especially bad if it hasn't rained in a few weeks
and there's a lot of "stuff" in the air. Rain water needs to be monitored
carefully, no matter where you live, if you count on it for pond water. My
rain problems aren't nationwide, let alone world-wide. Folks out in Arizona
near the copper mines would probably have a problem; other areas with
open-pit mining would have problems of their own, if only for the dust.

Lee

"Offbreed" wrote in message
...
Lee B. wrote:
we will die. Koi need certain levels also - HOWEVER, the *normal*
ambient
background salt in most water supplies is sufficient for their needs. At
least here in Central Florida. Don't know about the rest of you folks.

This would be a problem in areas where people used rain catchment
systems, such as in rain forests or areas with nasty water in the
public utility. Thanks, I'll try to remember this.