O dear, you've missed a little piece of the methodology! You only ever add ammonia at the "add-hour," the 24-hour mark after you dosed previously. Adding sooner than that or adding if your NH3 reading has not reached true zero ppm will eventually add too much nitrogen to the tank. Mind you, its no big deal, there's lots of latitude in things that eventually work out luckily! But we've found it works really well to do several tweaks in the fishless cycling process to help guard against too much NO2 and NO3 buildup during the second phase: "Pulse" the dosing (as described above) by letting it get down to zero and sit there until the 24hour mark is reached; lower the dose itself (personally I like 2 or 3ppm rather than 4-5ppm during the 2nd phase, then of course it needs to be eased back up to 5ppm for the finish during the 3rd phase.) During the third phase it works really well to do some giant water changes on some of the weekends, with redosing, to get those nitrogen levels down!
You can go a day or two before the fish are introduced (assuming its not a completely full stocking) after the big water change, but you can also (believe it or not) lightly dose some ammonia to the bacteria too, as, if you think about it, the big water change is really all about just getting the nitrate level down under control before the fish go in. Just make sure all parameters are A-OK for the fish (zero ammonia, zero nitrite, 15-20ppm above tap level as max for nitrate.)
~~waterdrop~~
