Aquarium Nitrogen Cycle Calculator
Created by: Liam Turner
Last updated:
Track your aquarium's nitrogen cycle progress by entering your ammonia, nitrite, and nitrate test readings. Calculate proper ammonia dosing for fishless cycling and get estimates on when your tank will be safe to add fish.
Aquarium Nitrogen Cycle Calculator
AquariumTrack cycling progress, calculate ammonia dosing, and determine when your tank is ready for fish
Current Test Readings (ppm)
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What is an Aquarium Nitrogen Cycle Calculator?
An Aquarium Nitrogen Cycle Calculator helps track the cycling progress of a new tank by estimating timeframes, monitoring ammonia dosing for fishless cycling, and providing guidance based on your current test readings. Understanding where you are in the cycle prevents the deadly New Tank Syndrome.
This calculator estimates cycle duration based on your setup, calculates proper ammonia dosing amounts, and interprets your test results to determine cycle stage.
Nitrogen Cycle Stages
Stage 1: Ammonia rises as bacteria colonize (Days 1-14)
Stage 2: Ammonia drops, nitrite rises (Days 14-28)
Stage 3: Nitrite drops, nitrate appears (Days 28-42)
Stage 4: Cycle complete - safe for fish (Days 42+)
Cycling Methods Compared
Fishless Cycling (Recommended): Add pure ammonia to 2-4 ppm daily until bacteria establish. Safest method - no fish harmed. Takes 4-6 weeks but creates robust bacteria colony.
Seeded Cycling: Using established filter media, substrate, or decorations from a cycled tank. Can reduce cycling time to 1-2 weeks if enough bacteria transferred.
Bottled Bacteria: Products like Seachem Stability or Fritz Turbostart can jump-start the cycle. Results vary - some complete in 1-2 weeks, others still need full cycling time.
Fish-In Cycling (Not Recommended): Using hardy fish to produce ammonia. Stressful and potentially fatal for fish. Requires daily testing and water changes. Only use as last resort.
Frequently Asked Questions
What is the nitrogen cycle in aquariums?
The nitrogen cycle is the process where beneficial bacteria convert toxic fish waste (ammonia) into less harmful substances. Ammonia → Nitrite → Nitrate. Ammonia and nitrite are toxic to fish even at low levels, while nitrate is tolerable up to 20-40 ppm and removed through water changes.
How long does it take to cycle a new aquarium?
A typical fishless cycle takes 4-8 weeks. With established filter media or bottled bacteria, it can be 2-4 weeks. Temperature, pH, and ammonia source affect speed. The cycle is complete when ammonia and nitrite both read 0 ppm within 24 hours of adding ammonia.
What are the signs that my tank is cycled?
A cycled tank shows: 0 ppm ammonia, 0 ppm nitrite, and some nitrate (5-20+ ppm) present. You should be able to add 2-4 ppm ammonia and have it process to 0 within 24 hours. Consistent readings over several days confirm the cycle is complete.
Can I cycle an aquarium with fish in it?
Fish-in cycling is possible but stressful and risky for fish. It requires very few, hardy fish, frequent water changes, and daily testing. Fishless cycling with pure ammonia is safer and more reliable. If doing fish-in, use bacteria supplements and keep ammonia under 0.5 ppm.
What ammonia level should I maintain during fishless cycling?
Maintain 2-4 ppm ammonia during fishless cycling. Start by adding ammonia to reach 2-4 ppm, then re-dose when it drops to 1 ppm or below. Don't exceed 5 ppm as very high ammonia can stall bacterial growth. Test daily and record your progress.
Why is my ammonia not going down during cycling?
Common causes: pH below 6.0 (bacteria struggle), temperature too cold (keep 75-85°F), chlorine/chloramine in water killing bacteria, or simply being early in the cycle. Ensure dechlorinated water, proper temperature, and patience. Cycles can take 6-8 weeks.
What is New Tank Syndrome?
New Tank Syndrome occurs when fish are added to an uncycled or partially cycled tank. Ammonia and nitrite spike, poisoning fish. Symptoms include gasping, lethargy, red gills, and death. Prevention requires proper cycling before adding fish or very gradual fish-in cycling.
Do I need to cycle a tank with live plants?
Yes, but heavily planted tanks cycle faster as plants absorb ammonia directly. Plants help but don't replace the bacterial colony needed for long-term stability. Light planting still requires full cycling. Some use the 'silent cycle' method with heavy planting and no fish initially.
Sources and References
- Aquarium Science, "Complete Guide to Fishless Cycling", Research Publications, 2024
- Aquarium Co-Op, "Nitrogen Cycle Explained", Educational Series, 2024