What is the goal?
Aquarium nitrogen cycling has been discussed indepth throughout this hobby. Often given as advice to beginners, many guides and articles have been written on this topic including detailed step-by-step instructions for cycling a tank.
Here, I will avoid repeating these guides and focus on water and some of the requirements to make water safe for fish and shrimp.
Nitrogen Cycle
The process of growing microscopic organisms (nitrifiers) that convert ammonia to nitrate is well understood.
Here is an article from the Aquarium Wiki
I have written a simpler guide for cherry shrimps HERE
Essentially involves adding ammonia sources over a period of time to grow a healthy colony of nitrifiers before adding fish or shrimp.
Plants
Plants and nitrifiers both uptake nitrogeneous waste, for different uses. Hobbyists have promoted using plants to boost or even skip the cycling process entirely.
For example, Diana Walstad's book and Father Fish Youtube channel promotes heavily planting a new aquarium.
Healthy plants can potentially allow fish or shrimp to be added right away.
Water
Water with very low dissolved solids and thus buffering capacity (ie rainwater) seem to be able to support fish without cycling.
Ammonia toxicity becomes insignificant as pH drops below 7.
Nitrite production may stop, and favor ammonia converting directly to nitrate (comammox). More data needed among hobbyists.
Toronto's Water
Toronto's tap water is hard and alkaline.
It does not seem to be safe for fish and shrimp right out the tap.
A cycling period is needed before fish or shrimp can be added.
Water conditioners/dechlorinators do not seem to be able to alleviate these effects.
GH and KH
Certain species seem to be sensitive to the amount of dissolved minerals and acidity of the water.
Example: Crystal Red Shrimp requires acidic water and a narrow range of TDS and GH. They will not flourish outside of those parameters even if the tank is cycled.
Nutrient Levels
'Nutrient' is an ambiguous parameter to measure. If too much food goes into an aquarium, shrimps will start to die even if the tank is cycled.
Potentially due to elevated levels of dissolved organic carbon, the types of dissolved organic carbon, the increased number of bacteria & microorganisms, or other factors.
Oxygen levels may also drop due to the decomposition of excess food.