Biomature is basically ammonia with the trace elements that are beneficial to the growth of the bacterial colonies. A normal cycle doesn't stall above 5ppm, I think that is one of those myths that has grown with the internet (of which there are many) in an attempt to find an explanation when something goes wrong. For years I have been cycling with a starting point of ammonia around 10ppm and each one has completed within 4 weeks. I get the ammonia to around 10ppm and let the cycle run its course. I monitor pH and alkalinity but have never had reason to adjust either of those during a cycle (but then I have always tended to live in fairly hard water areas). To keep the Nitrosomonas ticking along I add a weekly dose of ammonia during the course of the cycle.
In fact, the longest cycle I have had was when I started with ammonia at 4ppm. Of course, not saying that the starting level of ammonia was the cause as there are many factors that could have affected it. All the requirements of the cycle have to be kept in balance and these are (presuming there is a day food source available) pH, temp, light, oxygen, micronutrients (trace elements), salinity and toxins.
