Ill link this to the microbiology of cycling thread.
duration cycling doesn't vary, this tank is cycled. he's spent more than 30 days underwater with ammonia producing animals in place and an ammonia reading that doesn't rise e24h
Why test kits may or may not show it varies. use of Prime water conditioner, kitchen lighting, fw vs sw charts, reagent shaking and line fill, the variation never ends.
but what never ever varies is this:
this tank cannot have persistent .2 ppm ammonia, there's no biological mechanism for it.
two reasons
1. its holding vs climbing
2. this tank can pass a digestion test of likely 3-4+ ppm movement, not necessarily zero per your testing, and we can prove that if required you'll just need to remove your corals and fish for a sec. Since I can make that tank measure 3-4 ppm oxidation of ammonia in 24 hours when I get to use that test kit the way I want to, where .2 ppm equals zero then we boost to 1 ppm above that and check in 24 expecting .2, that means you have no way for it to hover at .2 or .25 as most other kits would show
when seneye monitors read .2 free ammonia, alert.
you'd have to be emitting a source of ammonia greater than 4 ppm in 24 hours...that water would be stinky and cloudy.
No mechanism exists for holding low level ammonia -that a titration kit will show accurately- in a four mo old reef. This is a mistest any way you slice it. even if your tester shows hard zero on distilled water calibration, you don't have free ammonia in that tank as I can't see a source of that much rot available for sustained input above what the tank can certainly already oxidize every 24 hours.
Good idea to have your LFS test the water though to be sure.
