Seachem Stability Fish Tank Stabilizer - For Freshwater and Marine Aquariums, 16.9 Fl Oz (Pack of 1)
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Availability:
In Stock.
Arrives
Monday, Mar 9
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Size: 500 ml / 16.9 fl oz
Color: Clear
Features
- TANK STABILIZATION: Seachem Stability will rapidly and safely establish the aquarium biofilter in freshwater and marine systems, thereby preventing the #1 cause of fish death: "new tank syndrome".
- TREATMENT: Stability is formulated specifically for the aquarium and contains a synergistic blend of aerobic, anaerobic, and facultative bacteria which facilitate the breakdown of waste organics, ammonia, nitrite, and nitrate.
- BACTERIA GROWTH: The necessary conditions for the growth of Stability's bacteria strains encompass a very broad range. When other bacteria begin to die off (usually from high organic loads caused by the unknown death of an organism), Stability simply becomes more effective.
- USE: Shake Seachem Stability well before use and turn off UV/ozone filter. Use 1 capful (5 mL) for each 40 L (10 US gallons) on the first day with a new aquarium. Then use 1 capful for each 80 L (20 US gallons) daily for 7 days. Fish and other aquatic species may be introduced at any time as long as dosage is maintained for 7 days.
Description
Seachem Stability Fish Tank Stabilizer - For Freshwater and Marine Aquariums, 16.9 Fl Oz (Pack of 1)
Brand: Seachem
Liquid Volume: 500 Milliliters
Item Weight: 1.1 Pounds
Item Form: Liquid
Manufacturer: Seachem Laboratories, Inc.
Is Discontinued By Manufacturer : No
Product Dimensions : 7.6 x 2 x 1.5 inches; 1.09 Pounds
Item model number : 123
Date First Available : June 20, 2004
Manufacturer : Seachem Laboratories, Inc.
Best Sellers Rank: #2,426 in Pet Supplies (See Top 100 in Pet Supplies) #9 in Aquarium Water Treatments
#9 in Aquarium Water Treatments:
Customer Reviews: 4.8 4.8 out of 5 stars (13,131)
Item Weight: 1.09 pounds
Manufacturer: Seachem Laboratories, Inc.
Item model number: 123
Date First Available: June 20, 2004
Item Package Dimensions L x W x H: 7.48 x 2.36 x 2.28 inches
Item Dimensions LxWxH: 7.6 x 2 x 1.5 inches
Item Weight: 1.1 Pounds
Brand Name: Seachem
Target Audience Keyword: all fish, fish
Directions: See Packaging
Country of Origin: United States
Model Name: Seachem Stability Fish Tank Stabilizer
Color: Clear
Size: 500 ml / 16.9 fl oz
Material: Liquid
Age Range Description: All Life Stages
Number of Items: 1
Style: Tank Stabilizer
Specific Uses for Product: Indoor
Frequently asked questions
If you place your order now, the estimated arrival date for this product is:
Monday, Mar 9
Yes, absolutely! You may return this product for a full refund within 30 days of receiving it.
To initiate a return, please visit our Returns Center.
View our full returns policy here.
To initiate a return, please visit our Returns Center.
View our full returns policy here.
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Top Amazon Reviews
Size: 500 ml / 16.9 fl oz
Color: Clear
When I set up a small quarantine tank last year, I underestimated how quickly ammonia can spike in a fresh system. Within a day, I was staring at test kit colors I didn’t like. That’s when I reached for Seachem Stability, and it’s been part of my tank-start routine ever since. 🧪 Cycling Support Stability is designed to introduce beneficial bacteria that help break down ammonia and nitrite. In my experience, it noticeably smoothed out parameter swings during the first week of a new setup. It’s not instant magic, but it definitely supports the biological filter getting established faster than doing nothing. 🌊 Water Stability What I appreciate most is how it helps reduce that “new tank unpredictability.” When dosing as directed, ammonia and nitrite levels tended to stabilize more quickly, especially when I was cautious with feeding. It gave me a bit more confidence during those early days. 🐟 Livestock Safety I’ve used it with both freshwater fish and planted setups without seeing stress reactions. It’s marketed as safe for fish, plants, and invertebrates, and I haven’t noticed any cloudiness or negative side effects when using the recommended amounts. 🧴 Ease of Use Application is simple — shake well and dose according to tank volume. The instructions are clear, and you typically use it daily during the initial cycling period. It doesn’t have a strong smell, and it disperses easily in the water. ⏳ Expectations It’s important to keep realistic expectations: you still need to test water parameters and monitor ammonia, nitrite, and nitrate. Stability supports the process — it doesn’t replace proper cycling practices. Patience and regular testing still matter. 💰 Value for Money Considering how much livestock costs (and how stressful ammonia spikes can be), a bottle of Stability feels like inexpensive insurance for new setups or after major filter cleanings.
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Reviewed in the United States on February 23, 2026 by SAM
Size: 500 ml / 16.9 fl oz
Color: Clear
I’ve been using Stability for years and very happy with it. The environment of the tank and water quality remains excellent between water changes and maintenance.
Reviewed in the United States on February 15, 2026 by Christopher Harrison
Size: 2 l / 67.6 fl oz
Color: Clear
Seachem Stability is a great product, very simple as it is that great nitrifying bacteria that turns fish waste or food from Ammonia to Nitrites and to Nitrates. Ammonia and Nitrites are severely toxic to fish so establishing a tank with this or seeding it with an already established sponge filter is essential to avoid "new tank syndrome" I have been using Seachem products and stability for months but stability and their prime has been staples for every water change to avoid a cycle crash among my API freshwater liquid master test kit. None of their products mess with water clarity, you will see a slight distortion as they settle into the water collumn, although this disperses rather quickly. I highly recommend.
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Reviewed in the United States on November 20, 2025 by Zach Zach
Size: 500 ml / 16.9 fl oz
Color: Clear
This stabilizer has been simple to use and fits smoothly into regular aquarium maintenance. Dosing is clear, and it integrates well when setting up or maintaining a tank. It’s performed consistently with no issues and does exactly what it’s designed to do. The bottle size is practical and should last through multiple uses. Straightforward, reliable, and effective.
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Reviewed in the United States on January 11, 2026 by KaninAngMandaragat
Size: 500 ml / 16.9 fl oz
Color: Clear
Works great! I was having issues with the nitrite being converted to nitrates because of lack of proper bacteria. I followed the 7 day dosage cycle and this completely turned the tank around. It’s stable and fully cycled now.
Reviewed in the United States on November 11, 2025 by Jazzmcb
Size: 2 l / 67.6 fl oz
Color: Clear
Excellent product fast shipping
Reviewed in the United States on February 6, 2026 by Jeff K.
Size: 500 ml / 16.9 fl oz
Color: Clear
Pros: -Fast-acting. I rely on it often during emergencies, and it's potent. For example, I recently used 3 caps on a terribly neglected 3-gallon tank of water with ammonia readings as high as 8ppm (-In other words, ultimately lethal to most any fish that don't have the ability to draw oxygen from the water surface like bettas and gouramis. And even they will eventually chemically burn their gills by breathing it in, anyway), and 8 hours later the ammonia readings came back at 0ppm. Cons: -Make no mistake; ammonia concentrations over .50ppm WILL kill the beneficial bacteria colony you're trying to estabilish from your bottle of Stability. If you really can't do a full water change and need to use this on an already highly polluted setup, use a generous amount of Seachem Prime to temporarily detoxify said ammonia so that the beneficial bacteria have time to eat it before it kills them. -It is not uncommon for a fresh bottle of Stability to arrive carrying pollution of it's own. I would suggest immediately using an ammonia test kit (-Do NOT use tests in the form of strips if you're new to aquarium keeping) on the contents of the bottle. If concentrations are higher than 1ppm you will likely only be adding dead microbes to your tank, and as they decay they will make things even worse for your fish. -Although harmless, large quantities of Stability can cloud your water. If you experience this and it really bothers you, take it as a sign that you need to cut back on the size of your doses. -Although it does have a decent life expectancy, do not assume your Stability will last until the purported use-by date. I would not recommend buying large bottles of it unless you know, for certain, that you'll be using it within a few months.
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Reviewed in the United States on April 12, 2021 by Brazen
Size: 500 ml / 16.9 fl oz
Color: Clear
I originally started ordering this Seachem product to stabilize my fresh water chemistry in which it does wonderfully. However, no Im hooked on it as it makes my water so clear. I added this product to my subscription list. Highly recommended. 55 gallon tank with many community fish that got much larger than i expected.
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Reviewed in the United States on October 31, 2025 by Tom