Try upping the amount of ammonia. And Stability apparently really doesn't do much -- what you want is a product called Bio-Spira. It's expensive, and is usually found in the
LFS' refridgerator if they have it. But reports here say it's the best and fastest way to cycle a tank.
7 days isn't much, considering the size of your tank -- folks here have reported it taking a month or more for a large tank to cycle. I'm going to assume you have the filter running 24/7, and it has some type of bio-media in it. I'm also going to assume you have the substrate in, and perhaps some decorations, if not artificial and real plants. The bacteria grow in all these places, and need them to have a home.