Originally Posted by Zombie
A summary would be wonderful.
As for tank b, it'll be
1 honey or dwarf gourami (undecided)
2 sparklilng gourami
1 male guppy
1 kuhli loach
I was multi tasking and not paying attention.
Here's a link to the full story: Aquarium Nitrogen cycle and cycling. Methods for ammonia, nitrite removal.
In summary, fish produce ammonia (through respiration, urine, excrement) as does decaying plant or animal matter (including fish food uneaten). Ammonia is highly toxic to all fish. A bacteria called nitrosomonas converts ammonia to nitrite; nitrite is also toxic although slightly less so than ammonia. A second bacteria called nitrospira (and possibly nitrobacter) convert nitrite to nitrate which is harmless except at high levels (more in a minute).
Nitrosomonas and nitrospira only appear when their food source appears, ammonia and nitrite respectively. But it takes time. When a new tank is set up, ammonia must be added (a hardy fish or two, fish food left to decay, pure ammonia, shrimp meat...) and usually within 5-9 days the nitrosomonas will appear. Once they start producing nitrite, the nitrospira bacteria will also appear within 4-8 days. The daily test for ammonia will show the ammonia rising and then begin to fall (as the bacteria take hold) and then the same with nitrite. Once both ammonia and nitrite have spiked and then fallen to "0" and stay there for several consecutive days, the tank is cycled for the bioload it contains at that time. During this cycling process, fish in the tank are under stress, and the more fish the worse; they can be killed outright. There are ways to relieve this stress; adding a healthy bacteria colony from an existing established mature tank (using filter media unwashed, gravel, even plants, wood and rocks) is one, another is using biological products like "Stability" (Seachem) or "Cycle" (Hagen). But the cycle still has to go through the motion, and the fewer fish in the tank the better.
Nitrate is required by plants (one reason plants in an aquarium are a help), some by anaerobic bacteria, and the majority we remove with regular weekly partial water changes.
It is your choice how you cycle (hardy fish or fishless). There has to be a regular supply of ammonia, or the nitrosomonas bacteria will die back, and similar for the nitrospira if there is not a steady supply of nitrite. I prefer using fish to cycle a tank. Following the "seeding" mentioned above (established tank stuff and Stability or Cycle) works well as the fish provide the continuous ammonia. And once the tank is cycled, adding new fish creates more ammonia and the bacteria need time to multiply to handle it anyway, so it is much the same thing in miniature. The trick is to get the bacteria established and then keep them going.