Cycle your tank fast — and stop new-tank fish deaths.The #1 killer of new aquarium fish is “new tank syndrome”: ammonia and nitrite spikes before the biofilter is established. Waiting weeks to stock is agony; stocking too soon is fatal.Seachem Stability rapidly and safely establishes the biofilter in fresh and marine tanks with a synergistic blend of aerobic, anaerobic, and facultative bacteria that break down waste, ammonia, nitrite, and nitrate. The bacteria are non-sulfur-fixing (no toxic hydrogen sulfide) and completely harmless to fish and plants — you can't overdose it.Seachem Laboratories, a chemistry-driven company since 1979, developed Stability in-house at its Madison, Georgia labs. Rather than relying on a single strain, its scientists engineered a synergistic multi-species blend — a hallmark of Seachem's effective, research-led formulations. Shake well; turn off UV/ozone. Dose 5 mL (1 capful) per 40 L (10 gallons) on day one, then per 80 L (20 gallons) daily for 7 days. Then dose monthly, with water changes, and whenever adding fish or medicating. Stock sooner, lose fewer fish. Add to cart.Why Seachem Stability Fast, safe cycling: establishes the biofilter quickly so you can stock without waiting weeks or risking ammonia spikes. Synergistic bacterial blend: aerobic, anaerobic, and facultative strains work together on waste, ammonia, nitrite, and nitrate. Impossible to overdose: the non-sulfur-fixing bacteria are harmless to fish, invertebrates, and plants. Pairs with your system: works best alongside biological media such as Seachem Matrix and complements the wider Seachem range. Best ForCycling brand-new freshwater or marine tanks, restarting the biofilter after cleaning or medicating, and maintaining biological stability whenever adding new fish.What It DoesRapidly establishes and maintains the biological filter in fresh and marine systems, preventing new-tank-syndrome ammonia and nitrite spikes. Harmless to all fish, invertebrates, and plants. Best used with biological media like Seachem Matrix.DirectionsShake well before use. Turn off UV/ozone. Use 1 capful (5 mL) per 40 L (10 US gallons) on the first day with a new aquarium, then 1 capful per 80 L (20 US gallons) daily for 7 days. Fish may be added at any time as long as dosing continues for 7 days. For ongoing performance, use 1 capful per 80 L (20 US gallons) monthly, with each water change, and whenever adding fish or medicating.Available Sizes250 mL, 500 mLFAQCan I add fish while dosing Stability?Yes. Fish may be added at any time as long as you continue dosing for the full 7 days.Can I overdose Stability?No. The bacteria are non-sulfur-fixing and harmless to all fish, invertebrates, and plants, so it cannot be overdosed.Does Stability work in saltwater tanks?Yes. It establishes and maintains the biological filter in both fresh and marine systems, and works best with biological media like Seachem Matrix.
