Just finished fish-in cycling a 12 gal tank (brand new tank/filter etc.) ... took about 6 weeks ...
Daily (sometimes twice daily) 40% to 50% water changes, use Prime ... water readings twice a day ...
First few weeks also used StressZyme and Stability frequently ...
Thought it would never end ... finally have had 10 days of 0 ammonia and 0 nitrites and nitrates no more than 20 ...
Just started water testing every other day and water change weekly, its like a vacation ...
Anyway the point being, I don't know how much the Stability & StressZyme helped (probably didn't hurt) but I believe that close monitoring of water conditions and frequent water changes got my buddies (no loses and everyone appears to be healthy and active) and me through it ... good luck