Home › Calculators › Fishless Cycle Ammonia Dosing Calculator Free aquarium tool · updated May 2026 Fishless Cycle Ammonia Dosing Calculator Free fishless cycle ammonia dosing calculator. Enter tank volume + target ammonia ppm, get the exact mL of pure ammonia (Dr. Tim's, Janitorial Strength, or Ace Hardware) to dose. Cycle in 4-6 weeks.
TL;DR Calculate exact ammonia drops to add for a fishless cycle. 2-4 ppm during cycling = ideal. Common ammonia sources: Dr. Tim's Ammonium Chloride (10%), Ace Hardware Janitorial Ammonia (10%), pure NH4Cl powder (mixed to 10%).
Ammonia volume to dose + frequency
Calculate dose
How to use this calculator Fishless cycle protocol:
Day 1 Dose ammonia to 2-4 ppm. Add bottled bacteria (Dr. Tim\'s One and Only, Bio-Spira, Stability) per manufacturer instructions.
Days 2-7 Test daily. Once ammonia drops below 1 ppm, re-dose to 2 ppm. Watch for nitrite to appear (week 2-3).
Days 14-28 Continue dosing ammonia to 2 ppm whenever it drops to 0. Watch nitrite peak then drop. Nitrate accumulates.
Cycle complete When dosed ammonia converts to 0 (and nitrite to 0) within 24 hours. Do a 50% water change before adding fish to drop nitrate.
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