I have to disagree. my research on this points to that a heterotrophic bloom does not compete with the autotrophic nitrifying bacteria, Hetrotrophs break down the uneaten food, fish waste, dead plant matter, dead animal matter, etc. into ammonia and feed a cycle. they rapidly multiply and consume the excess waste that needs to be broken down so that the autotrophic nitrifiers can then feed on the ammonia they produce as waste, when they heterotrophs consume the resource, they downsize and die off and the bloom ends. the danger of a bacterial bloom is when they bloom they switch to aerobic, rapidly multiply and consume oxygen along with the resource they are consuming that caused the bloom. a tank can go low o2 and cause stress on fish, and along with the ammonia they produce create a deadly situation for the fish..
Now, Diatoms, During photosynthesis diatoms use energy from light to convert water and
carbon dioxide into sugars for food. they use ammonium, ammonia and urea for reproduction and they multiply at a speed much like heterotrophs, diatoms use silicates to build their outer casing. Diatomaceous Earth are dead diatom carcases/fossils it's their shells.
A
diatom is a photosynthetic, single celled organism, or phytoplankton. they are the smallest form of food (I think) in the food chain and feed zooplankton, most freshwater tanks don't have zooplankton at least not at first.
Diatoms will bloom, consume CO2 and Light and silicates and produce oxygen, and die off when they consume resources, and then produce ammonia with the die off like everything else does when it dies and gets broken down in the nitrogen cycle. Diatoms do compete with the autotrophs to an extent but compete as low order plants would, or algae, and the end result of the die off is ammonia/ammonium.
Diatoms around the world are the largest biomass on the planet and account for 20-50% of the oxygen production annually.
These are all natural systems to make water livable and a balanced ecosystem. On a large scale. it's mostly seemless with one feeding another, the diatoms feeding the zooplankton, or consuming CO2 and producing O2 using ammonia and dying off in their reproduction cycle, and the heterotrophs feeding on the dead diatoms and the dead everything else and breaking them down into ammonia and consuming oxygen, and the nitrifiers consuming the ammonia and oxygen creating nitrates, and then Plants use nitrates as well as denitrifying bacteria in low oxygen anoxic zones that are hard to replicate in an aquarium which is why water changes are recommended to remove excesses. It all goes full circle and why it's called a cycle.
in the case of heterotroph or diatom blooms, the end result is ammonia when they exhaust the resource that caused the bloom and they die off back to reasonable numbers and become "fixed" again and out of sight.
