I'd made a 300ml starter and the only thing I hadn't done is aerate the wort.
I bought a 2micron stainless steel airstone & HEPA air filter from http://www.Beertech.co.uk as they were very reasonably priced. Only to find that these items have 1/4" fittings and my puny aquarium pump is both too pathetic & only equipt with 1/8" fittings.
Solution?Very sucessful & cheap
12v air compressor ~£10.
Use 3/8" OD plastic beer hose to connect it all together, chop the tyre valve connector end off of the pump & use a 1/4" hose joiner -> I also chopped the cigarette lighter socket off & fitted a couple of crocodile clips for using a seperate battery.

Works a charm if a little over zealous, probably only need ~ 3minutes of wort aeration with one of these on the go.
Frothy