turbostart 9000, and two clown fish.
It's the TurboStart that is preventing the ammonia from rising. The TurboStart product specifically (and not Dr. Tim's One and Only or Seachem Stability or any others) is the fastest acting of these bacteria-in-a-bottle products, and the only one where you can add fish in the first 24 hours or so and not experience an ammonia spike.
The bacteria contained in TurboStart are heterotrophic bacteria that are able to very quickly process ammonia to keep it safe for fish, but these are not the autotrophic bacteria that you really want for your biofilter long term. Think of the TurboStart like a bandaid. You still need to allow the slower growing autotrophic bacteria time to populate, but the TurboStart keeps the ammonia low until then.
A few other thoughts that I hope will help:
The API test kits don't get a lot of love here on R2R, but that's entirely blown out of proportion. The API kits have some quirks (like almost all home hobby level set kits), but they are by and large just fine, especially for the initial nitrogen cycle.
Ammonia is not as toxic as many believe, here's some numbers from RHF on ammonia toxicity from this link:
https://www.reef2reef.com/ams/ammonia-is-our-friend.1062/
From the above link:
1. While ammonia is toxic at high levels, the levels needed to be lethal to a marine fish are higher than many people think. I’ve not seen any study in the literature that shows an LC50 (half of fish die) in less than 15 ppm total ammonia in seawater over 4 days or more of exposure at normal pH.
2. Sublethal toxic effects of ammonia, such as gill lesions observed by histopathology, do not seem to become significant until levels reach 5-10 ppm total ammonia at pH 8.1.
3. The toxicity of ammonia is a function of pH. At pH 8.5, toxic effects kick in at ammonia levels 2.5x lower than at pH 8.1. Likewise, at pH 7.8, it takes twice as much ammonia to be toxic as at pH 8.1. In a situation where ammonia might well reach toxic levels, such as a shipping bag, raising pH in the bag should not take place.
4. Toxic levels of ammonia are just not reached in typical operating reef aquaria. Seeing a measured value of 0.2 ppm, whether real or test error, is not a concern. It may be a benefit.
Nitrite is non-toxic in marine aquaria (unlike in freshwater), and there's no reason to test for nitrite or be concerned with it at all:
https://www.reef2reef.com/posts/4805029/
Good luck!
