Bart said:
Gordon - thanks for the "turn the pump off first" idea! It's so brilliant and obvious, but the thought never occurred to me. I just pictured myself trying to shove a smaller pipe into the return line as water rushed out.
Yeah..I figured that one out after spending 10 minutes trying to get the eyeball back into MY return with the pump running.
What if I used one of those little pumps for backyard water features to pump the water up into the air? I know I won't get a huge spray dispersion and a ton of aeration from a tiny pump, but the one I bought has a 2.5 ft head so I know I can get the water out if the pool and into the air.
I think that's a fine idea!
The thing to keep in mind is WHY aeration works.
Aeration is all about surface area...the more water molecules you expose to the air, the more effect you'll get. (Oxygenation, pH increase, etc). So, at least to a point, the efficiency of your DIY rig will be dictated as much by how you disperse the water than by how MUCH water you move. Moving 1 gallon of water by pouring out of a bucket will be LESS effective than moving a half gallon through a fine mister.
So, design your system with the "sprinkler head" in mind. The more holes, and the smaller they are (while not putting undue strain on the pump itself) the better your system will perform.
As a side note, we often faced some of the same issues in aquariums as in pools, regarding wanting to aerate water, ESPECIALLY those of us that dosed with CO2 generators.
It's at least worth noting in any discussion about aeration that it doesn't HAVE to be performed by passing water through air. Passing air through water works too.

So if anyone's ever up for it (or maybe I will be some time *heh*) and air compressor and some tubing hooked to, oh, maybe some soaker hose, would probably do the job very nicely.
One last note...Just a future reference (or for others who come along in the future)...harbor freight has RIDICULOUSLY inexpensive pumps that move significant water at quite usable head pressures. I've got 3 in my 300g pond out front, and all are going on their 4th season, having outlasted the much more expensive pumps from the local aquarium/pond shop.