The Three Tools
Tool 1: bottled bacteria (Dr. Tim One and Only, Tetra SafeStart, Seachem Stability). Pick the freshest bottle — bacteria die in storage.
Tool 2: seeded media from an established tank — sponge, ceramic rings, or filter floss. The faster route.
Tool 3: pure ammonia or fish food as the nitrogen source.
Day-by-Day Schedule
Days 1-2: dose ammonia to 2-3ppm, add bacteria. Drop seeded media into filter.
Days 3-7: test daily. Once ammonia shows 0 and nitrite shows 0 within 24 hours of dosing 2ppm ammonia, cycle is functionally complete.
Days 8-12: maintain ammonia at 1-2ppm to keep bacteria fed. Add nitrate-eating live plants if planned.
Days 13-14: large water change (50%) to drop nitrate. Stock first 20% of the planned bioload.
- ✦Heat to 84°F to accelerate bacteria reproduction
- ✦Aerate heavily — bacteria are aerobic
- ✦Light is irrelevant for bacterial cycling
When It Fails
Most failures: dead bottled bacteria, ammonia dosed too high (above 4ppm), pH crash below 6.0 stalling cycle, or no carbonate buffer.
KH below 4 dKH causes pH instability that stalls cycling. Add a piece of crushed coral if KH is low.
Stocking Plan
Add hardy fish first (zebra danios, gold barbs, white cloud minnows). Wait 7 days before adding more.
Stock to 50% of capacity in week 3, full capacity by week 6. Bacteria need time to scale up to bigger bioloads.