Why this tool
The nitrogen cycle converts toxic ammonia (from fish waste and decay) into nitrite, then nitrate. New tanks need time for beneficial bacteria to grow. This tracker reads your test kit numbers and suggests whether the tank is still cycling, toxic, or ready for gradual stocking.
How to use
- Enter days since you filled the tank or started fishless cycling.
- Enter ammonia, nitrite, and nitrate (ppm) from a liquid test kit or strips.
- Read the stage, next action, and livestock risk — then follow the editorial guide below for context.
FAQ
What ammonia level is safe?
For most fish, keep ammonia at 0 ppm; anything above 0.25 ppm is stressful or lethal depending on species and pH.
Nitrate above 5 ppm means cycled?
Often yes when ammonia and nitrite read 0 — but confirm over several days before adding many fish.
Fish-in vs fishless cycle?
Fishless is safer. If cycling with fish, small daily water changes and heavy testing are mandatory.