"DD DDD" wrote in message
...
My 300 gallon preform has no waterfall or fountain. Can I just use a air
pump? Is there a small outdoor model? Or should I just get a indoor one
and keep it out of the weather? I have a bio/mech filter with a 1800 gph
pump that keeps everything clean. But the good bacteria it says need
oxygen as do the fish. So far the fish seem ok. Thank you


As long as the water is circulating around the pond, and the fish load is
low, the pump should be sufficient. Try and maximize circulation by drawing
water into the pump as far as possible from the return from the filter. The
fish will notice the lack of oxygen before the bacteria do. Use your eyes
and nose to give you clues, if you notice the fish are gulping air bubbles
or hanging out near the surface or you smell a swampy smell it should be
clue that the oxygen levels are insufficient.

-S