Seachem Stability

Seachem Stability is a fast-acting biological filter starter that safely establishes the beneficial bacteria your aquarium needs, in both freshwater and marine systems. It is the go-to bottled bacteria supplement for anyone setting up a new tank in South Africa, helping you sidestep the ammonia and nitrite spikes of "new tank syndrome" so you can stock fish sooner and with confidence.

How It Works: Stability delivers a balanced blend of aerobic, anaerobic and facultative bacteria that colonise your filter, gravel and surfaces, breaking down fish waste, ammonia, nitrite and nitrate. The strains are non-sulphur fixing, so they never release toxic hydrogen sulphide, and the formula is completely non-toxic — it is impossible to overdose, which makes it forgiving for first-time fishkeepers.

Key Benefits:

• Rapidly cycles new aquariums and re-seeds the biofilter after cleaning, medicating or a power outage.
• Works across freshwater, tropical, coldwater, planted and marine/reef tanks.
• Prevents the ammonia and nitrite spikes that stress or kill fish in a new set-up.
• Safe with fish, shrimp, snails and live plants, and will not cloud the water.
• Shelf-stable with no refrigeration required, and a shelf life of roughly 4 years.

How to Use & Dosage: Shake the bottle well before each dose and switch off any UV steriliser or ozone while dosing. One capful equals 5 mL.

• Day 1 (new set-up): add 1 capful (5 mL) for every 40 litres of aquarium water.
• Days 2 to 7: add 1 capful for every 80 litres, once daily, for a full week.
• Ongoing: dose 1 capful per 80 litres monthly, with every water change, and whenever you add new fish or medicate.

Fish and other livestock may be introduced at any point, provided you continue dosing for the full 7 days.

Sizes Available: Choose the bottle to match your system — 50 ml, 100 ml, 250 ml, 325 ml and 500 ml and 2L. The smaller bottles suit nano and single-tank set-ups, while the 500 ml is the best-value option for large aquariums, marine systems or fish rooms running several tanks.

Suitable For: New tank set-ups, restarting a filter after a deep clean, rebuilding a biofilter after antibiotic treatment, and topping up beneficial bacteria whenever livestock is added — across freshwater, planted, goldfish, tropical and marine aquariums.

Frequently Asked Questions

Can I add fish straight away when using Seachem Stability?
Yes. You can add fish from day one, as long as you keep dosing Stability every day for the full 7-day course. This is what allows it to cycle the tank safely while livestock is already present.

Is Seachem Stability safe for marine and reef tanks?
Absolutely. Stability is formulated for both freshwater and marine systems and is safe for fish, corals, shrimp, snails and live plants. The dosage is identical in either system — 1 capful per 40 litres on day one, then 1 capful per 80 litres daily.

Does Seachem Stability need to be kept in the fridge?
No. Unlike some live bacteria products, Stability is shelf-stable and does not require refrigeration. It carries a shelf life of around 4 years from manufacture, so a bottle keeps well between set-ups.

Can I use Stability together with Seachem Prime or medications?
Yes. Dechlorinate your tap water first with a conditioner such as Seachem Prime, then dose Stability — the two work well together. You can also re-dose Stability after medicating to rebuild any bacteria knocked back by treatment.

Which size should I buy for my tank?
A 50 ml or 100 ml bottle is ideal for a single small or nano tank, the 250 ml and 325 ml suit medium community aquariums, and the 500 ml offers the best value for large tanks, marine systems or keepers cycling several tanks at once.

What is the difference between Seachem Stability and Pond Stability?
Stability is dosed for aquariums in both freshwater and marine, while Pond Stability is concentrated for the far larger volumes of decorative and koi ponds. For an indoor fish tank, standard Stability is the one you want.