Freshwater cycle

Question
I recently purchased a 20 gallon aquarium, and like many others had no idea of the nitrogen cycle when I bought it, and of course the ladies at the pet store, who were very nice and trying to be helpful, never mentioned it and encouraged me to add fish after a week.

I have since learned a bit about the nitrogen cycle, and am regularly testing my tank for ammonia, nitrate and nitrite levels. I began this when I learned that my ammonia was so high it was past registering on the chart.  Of course, I have lost several fish as a result.

It has been three weeks of monitoring, and while my ammonia level is coming down, I am not registering any nitrite or nitrate at all yet.  I am using a liquid bacteria additive. I have also been doing a 50% water change every other day to bring down the ammonia, it appears to be working (but not as fast as I'd like of course).

I have no plants in the tank, only some rocks (from the pet store) and a couple decorations (also from the pet store).  I have 5 glow fish, a balloon molly, a red wag platy, four cat fish and 2 algae eaters (whose name I cannot recall).  All seem to be doing well now that I am doing frequent partial water changes, but the ammonia is still at between 2.5 and 4 PPM when I test.

Is there something I can do to get the nitrite/nitrate cycle moving along?

Answer
Gary,
Unfortunately, most large pet stores know nothing about the fish they sell. I always recommend cycling the tank without fish. The first thing that will register is the ammonia. If it is not taken care of, it turns into nitrites. I suggest that you stop using the liquid bacteria. It really does nothing to help the tank. Just keep checking the water daily and do water changes accordingly.