I agree, all you need is a small airstone. I usualy use 1" air stones, unless there is a large fish in the tank like my Murray cod, where I use a 2" (5cm) ball to keep it on the bottom of the tank.
A cc is a Cubic Centimetre, about 16cc = a cubic inch. Unfortunatly America does not use standard scientific units and persists with Imperial measurements. A few years ago (and maybe still) America was the ONLY country in the world that did not use or was not changing to metric. Oh well I guess a few more space probes will have to crash into Mars before they change *[img]http://www.**********.com/iB_html/non-cgi/emoticons/wink.gif[/img] *I would feel that 1200cc/min would be ample.
The main use of an air stone is to get fresh air into a tank. A lot of the gasses produced by a tank like CO2 and methane etc. are heavier than air and will sit on the surface of the water reducing oxygen exchange. If you rely on something lke your hang on filter to oxygenate the water you can simply end up circulateing the stale air. If you have good air circulation and surface agetation, an air pump will make little difference but if you have cover glass or a hood on the tank I would strongly recomend an airpump.
If you arer cleaning your fileter every week I would feel this would be bad for the tank. Not so much the cleaning but the destroying of your filter bacteria. I would sugest adding some other filter media, like ceramic noodles some how [img]http://www.**********.com/iB_html/non-cgi/emoticons/confused.gif[/img]
Also never forget that plants can be a very effective filter as some species feed directly of the ammonia produced by the fish reducing the bioload on your filters. I have a saying that if you set up a tank to grow plants well, you will have healthy fish! Do you have plants in your tank and if so are they growing well (growing well means that you have to remove excess plants on a regular bassis)?
Sounds like we are getting somewhere!
Best of luck,