Ann, I had the same concern and problem as you. Instead of taking chances,
I simply compromised by lifting the cover a little bit higher. Floating was
not a choice for me though since I have plants in my pond, and I am
convinced that the impact in terms of air exchange, and a fish possibly
getting on top of the cover and getting trapped or dying.

I used a shade cloth from home depot, add eyelets at the corner and hung it
from 4 galvanized pipe posts that I had driven into the ground Works great,
looks great. And can be rolled up when I have company to fully expose the
pond in it's complete beauty.

--
_______________________________________
"The difference between 'involvement' and 'commitment' is
like an eggs-and-ham breakfast:
The chicken was 'involved' - the pig was 'committed'."

http://community.webshots.com/user/godwino

"ann in houston" wrote in message
om...
Did y'all miss me??? I'm back too, this season, along with several
other "old-timers" that I've seen post about returning after an
absence. And, of course, I have a question. DH wants to float a
screen-like cover on the pond surface to shade it and keep the algae
down. I am uncomfortable about what that will do to the O2 exchange,
even if the material is porous. This seems like it would be
especially bad once our summer heat really kicks in. Or, would the
lack of sunlight compensate and keep the water cool enough to help the
water retain its oxygen? A cover of some kind does seem to be in
order, but we are dithering (and bickering)over the design.
TIA,
Ann