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API

API NITRITE TEST KIT 180-Test Freshwater and Saltwater Aquarium Test Kit

  • Based on 3,259 reviews
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Availability: In Stock.
Fulfilled by Amazon
Arrives Monday, Aug 24
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Size: 180 tests


Features

  • Contains one (1) API NITRITE TEST KIT 180-Test Freshwater and Saltwater Aquarium Test Kit, including 1 bottle of testing solution, 1 color card and 1 test tube with cap
  • Helps monitor nitrite and prevent invisible water problems that can be harmful to fish
  • Accurately detects high nitrate levels from 0-5 ppm
  • Prevents high levels of nitrite which inhibit fish respiration and suppress their immune systems
  • Use for weekly monitoring and when water or fish problems appear

Description

Keep your fish healthy and thriving by testing your aquarium water's NO2 levels regularly with this easy-to-use API NITRITE TEST KIT for freshwater and saltwater aquariums. Testing water parameters weekly helps prevent invisible water problems that can be harmful to fish. Nitrite is produced in the aquarium by fish waste and uneaten fish food. Low levels of nitrite inhibit respiration and suppress the immune system; high levels cause suffocation. The API NITRITE TEST KIT tests for harmful nitrite levels from 0 to 5 ppm. This product comes with one nitrite bottle, one capped test tube, one instruction manual and one color card. API NITRITE TEST KIT can be used in freshwater and saltwater aquariums. With API aquarium products, it’s easy to keep a beautiful saltwater, freshwater or reef aquarium. For almost 60 years API has developed premium solutions with proven and effective results for your family and ours. API offers a range of testing kits, water conditioners, and nutritionally superior food, because we’re dedicated to making a better underwater world. They work to provide a safe, hospitable environment for fish such as tropical community fish, cichlids, goldfish and more. At API, we understand the rewards and relaxation of fishkeeping because we have a passion for fish too.

Item Weight: 2.4 ounces


Department: men, women


Manufacturer: Mars Fishcare


ASIN: B000255NC8


Item model number: 26


Customer Reviews: 4.7 4.7 out of 5 stars (3,259) 4.7 out of 5 stars


Date First Available: June 20, 2004


Item Package Dimensions L x W x H: 5.08 x 4.45 x 1.69 inches


Item Dimensions LxWxH: 1.5 x 2.38 x 5.13 inches


Item Weight: 68.04 Grams


Brand Name: API


Target Audience Keyword: fish


Directions: Water should be tested for nitrite every other day when your aquarium or pond is first set up, and once a week after the biological filter has been established (in about 4-6 weeks).


Model Name: FW/SW NITRITE TEST KIT


Color: No Color


Size: 180 tests


Material: Plastic


Number of Items: 1


Manufacturer: Mars Fishcare


Style: Nitrite


Frequently asked questions

If you place your order now, the estimated arrival date for this product is: Monday, Aug 24

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.

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Similar Products

Top Amazon Reviews

    • Much better than test strips Much better than test strips
Size: 90 Tests
Review Image by Joshua Duff
I’ve been using the API Nitrate Liquid Test Kit for a while now and it’s been rock solid. The instructions are clear, the bottles are easy to work with, and the color chart is straightforward to read under normal lighting. I appreciate that it’s a true liquid test and not strips, so the results feel much more reliable and consistent. The test has helped me stay on top of nitrate levels in my tanks and catch trends before they become problems. The reagents last a long time, and as long as you follow the directions and shake bottle #2 thoroughly like it says, the readings are repeatable. Overall, it’s accurate, dependable, and worth having if you care about water quality. I wouldn’t hesitate to buy it again. ... show more
Reviewed in the United States on February 23, 2026 Reviewed in the United States on February 23, 2026 by Joshua Duff
    • Good value for the money
Size: 90 Tests
Excellent product, good value for the money.
Reviewed in the United States on May 25, 2026 by David Del Valle
    • Reliable and Easy-to-Use Kit
Size: 90 Tests
This Aquarium Water Test Kit is reliable, easy to use, and very helpful for keeping aquarium water safe. It provides accurate nitrate readings for both freshwater and saltwater tanks, making it great for monitoring water quality and preventing algae problems. The kit includes clear instructions and enough tests to last a long time. ... show more
Reviewed in the United States on May 10, 2026 by Hrob
    • Works perfectly fine!
Size: 90 Tests
This test works perfectly fine. If people say it doesn't work then they're doing it wrong, just be sure to follow the instructions. It's pretty quick to use and last for quite some time so it's totally worth it, plus the test strips are not very accurate.
Reviewed in the United States on February 1, 2026 by Fish mama
    • Ask yourself - Does it have Orange when looking at results.
Size: 90 Tests
This Nitrate test is very good. Honestly, I used both the Salifert and API versions and they both work good. What is nice about the API version is that you can use the acid to test if rocks have carbonate in them by dropping a couple of drops on a rock to see if it bubbles. (look it up). Also, about the colors. It gets hard to distinguish the colors. The way that I do it, is I ask myself "does it have orange in it? If so, then it is one of the Orange. Then I ask myself if there is no orange then it is red! Or if their is no orange then it is Yellow. Seriously! Try it!. Do the test. Ask yourself if it has orange, or STILL has orange. it will then be easier to match to the card! I hope I explained that well. Good Luck ... show more
Reviewed in the United States on April 21, 2025 by Mark Agostinelli
    • Great Test Kit for the price, it gives you a pretty good estimate of your Nitrates when they are high.
Size: 90 Tests
API kits are fairly accurate for the price, I highly recommend them for salt water aquarium owners that need and should have at least 2 kits of every important test type so they can cross reference results if they feel something is wrong with a particular test result. API fills that niche perfectly with pretty accurate easy to use kits that cost a quarter the price of the more accurate ones like Salifert, ELOS and Red Sea Pro. The API Nitrate Kit is as simple as it gets, just fill the vial to the marker or better yet use a syringe and add 5ml as directed. Then add 10 drops of reagent "A". swirl for a bit then shake reagent "B" for 30 seconds very vigorously and add 10 drops of that. Shake the whole thing for one minute vigorously and then wait 5 minutes to get a result. IMPORTANT NOTE: If you forget to shake reagent "B" you might as well throw the whole bottle of reagent out. This solution separates out in the container after a few hours into layers of different chemicals. If you don't shake it, you will be dripping out 10 drops of just one of those chemicals and remaining mixture will be compromised. The end result is that the next time you use it and shake it up properly the typically result is a lower reading than normal. Just remember to always shake reagent B properly for 30 seconds and you wont have any problems. If your Nitrates go down to reading Zero on the API kit, then it's time to move to a more accurate kit that is designed to read very low Nitrate levels. If your keeping a SPS Reef Tank you need the Nitrates to be near Zero and the API kit will not be accurate enough to read the small amounts that may be in your aquarium. For FOWLR Tanks, Nitrate is not as not as big of an issue, so an API kit or two is all you will probably need. ... show more
Reviewed in the United States on March 26, 2016 by Robbyg
    • Good product, will buy again as needed.
Size: 90 Tests
This product works very accurately. Nice to be able to buy this separately and not purchase the whole kit. More expensive then the strips but I trust this process.
Reviewed in the United States on November 25, 2025 by Karen from Chico, CA
    • Bien
Size: 90 Tests
Buena compra y mi hija esta muy satisfecha ,para el uso de sus peces
Reviewed in the United States on May 4, 2026 by Alisabel

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