"Newbie Bill" wrote in message
m...
I have a small 200 gph pump (very low power usage) submerged in my pond
for
additional aeration - just as added 'insurance'. The output is below the
water so the water is just 'bubbling' like a natural spring might. I do
not
want it splashing for several reasons. I have been told it is the
breaking
of the surface which helps to oxidize the water.
Questions: 1) Is this actually doing me some good. 2)Aesthetics aside
would
an airstone attached be significantly better.
Thanxx
Bill Brister - Austin, Texas



Try making a venturi out of pvc. This will give you the circulation benefit
of the pump with more aeration than an airstone. You can also make it for a
couple of bucks, so it's cheap to try.

Basically, your pump output goes into a piece of horizontal 1/2" pvc a
couple of feet long. Cut the pvc in half and add a T with the opening
pointing straight up. Get another piece of pvc long enough to fit in the T
and stick a couple inches out of the water. Cut one end at a 45 degree
angle and shave the pvc so it will fit past the stop in the T. It needs to
get down into the T and get into the flow coming from the pump, with the
open angle away from the pump. The water flow sucks air in from the upright
pvc and bubbles out of the lower pipe.

Here's a possibly better explanation, with a different method. With a small
pump, I'd stick with 1/2" pvc and shaving the pvc may be easier than finding
tubing that will fit inside the 1/2" pvc.

http://spaghoops.com/pond/venturi.htm

I'm also in Austin btw. My fish love playing in the bubbles, although I've
got a 1600 gph pump on the venturi which gives them a pretty good current to
play in.