Details of how you are cycling would help, as I and others have said just leaving a tank running is no good. If you want to cycle with fish then 24-48 hours after setting up put three hardy fish in, a week after, three more and so on. I would highly reccomend getting your own master test kit if doing this or a fishless cycle. I have cycled with fish and lost none, but are they happy fish? I will fishless every time from now on.
The water tests your LFS should be doing are ammonia (produced by fish or added by you), nitrite (produced by the bacteria that process the ammonia once established) and nitrate, often in tap water, but also produced by the bacteria that process nitrite. This is where water changes are important. Nitrate is the least toxic to fish, but still toxic.
I am not saying forget your LFS advice, just dont take it as 100%, they are not letting you buy fish yet, so are better than most.
Jon