The only bacteria that will remain completely dormant are spore formers and I doubt that they are the bacteria that you want. I used to have 50 tanks, have kept fish for years and have never used any product to cycle other than the bacteria I want, stolen from another tank by running the filter in there for a while, or by heavily planting the tank then adding fish slowly so that the balance is maintained. In my opinion many of these products, like chemicals to eliminate chlorine from Christchurch water (which has none) are a way for people to make money. Throw all the rubbish out, your fish will be grateful.