Over 5PPM of O2 is what you are shooting for. Some species can do with less.
Go to your pet store and get an O2 test kit and measure. With a 4000 gallon
pond and a waterfall I highly doubt you need to aerate to add more O2 to the
water.

"noone" wrote in message
...
Hi all,

I have a 4,000 gallon pond with a waterfall, which provides some
oxygenation. I
have been told that I need substantially more oxygenation.
Can anyone tell me how much is enough....is there a thing as TOO MUCH?
My fish load is pretty heavy but my essential water quality numbers are
great.
Thanks, in advance.
Happy ponding.
George