Bill,
For the 1/20 HP approx .75 pump I went with a Gast model MOA-175-AA pump. I got a new one off E-bay for $55 including shipping, a filter & the outlet plug.
I'm still not sure where I'm going to put it, but so far I'm leaning towards a spot between the rafters at the ceiling of the basement so it can run down-hill the entire way but still be inside. I really want to keep it inside so it lasts as long as possible.
I would rather not test out the big bubble theory as I have nothing to test against. Even if I tried big bubbles this year and small next year the temperature wouldn't be consistent so I wouldn't be able to draw any conclusions....that is unless someone wanted to give me an additional $75 for another pump, line & stone in the interest of science.
Anyways, if nobody wants to donate a pump to me for this "scientific" study I would prefer to start with a diffuser since the pond really needs as much air as possible (no flowing water) and that is almost as much of a concern as the ice freezing.
Thanks again for all your help. Hopefully I'll get a chance to call Home Depot and pick up a couple bundles of tubing.
