I just got done with my cycle, from using the product..according to their information it can last up to a year in the fridge..I have no Idea, I did have it in the fridge a couple of weeks before I used it though.MY cycle went two weeks..once I added the water, rock, sand I tested the parameters for a base line. then I added the bacteria, and recommended amount of ammonia..then I tested everyday at the same time of day...I didn't find out until about 12 days in that you are suppose to add more ammonia when it comes down to .25 so after day 12 I started doing that..And I still had a two week cycle, so I am not sure it made much of a difference. I would recommend adding the ammonia as directed.
also note, it does not have the recommendation of adding more ammonia with the product, I had to research that..But, I would do it..it will only help your cycle.