Thanks for the response, yes I've read the guide to fishless cycling, pretty technical. I can see though that that's the way to go if you really want to know whats going on with your microbes. I'll have to source some ammonia. I've never had much luck with my test kit, at least I never got any significant readings on anything, always at the low end of the scale. Perhaps I did everything right with my 20 gallon during its break in or I was lucky. I followed the test kit instructions exactly.
Not sure where I'll find the ammonia, in the mean time should I throw in a pinch of fish food to supply ammonia as it breaks down?
Also, the filter output is below the water line and doesn't make any bubbles, will it oxygenate the water enough or will I need to add an airstone?