Too lazy to read'em all and figure out which the heck tank and how the heck long! You might need to remind us.. is this the 54L little tank and its being fish-in cycled?
Regardless, assuming you are fish-in cycling and I'm right remembering that part, then your goal is to get two full days of zero readings for both poisons without doing any water changes. (This test would work fine even for you with your 0.25ppm ammonia in the tap water because its based on no water changes of course.) Probably most people would then keep watching it for a week, but basically it should mean its cycled.
~~waterdrop~~