API Ammonia NH3/NH4 Freshwater & Saltwater Aquarium Test Strips, 25 count

Rated 4 out of 5 stars
$16.98Chewy Price
$23.98Chewy Price
$16.13Autoship Price
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About This Item


  • Easy-to-use strips you dip directly into your aquarium's water.
  • Designed to detect even small levels of ammonia (0-6 ppm).
  • Highly precise color charts are easy to read.
  • The chart includes recommendations on how to treat the water and neutralize ammonia.
  • Test strips are safe for use in both fresh and saltwater aquariums.

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Play Video: Learn More About API From Our Team of Experts
Learn More About API From Our Team of Experts

Help protect your fish and neutralize ammonia with API's Ammo-Lock Detoxifier.

About API Testing

Testing the Waters

For fish to thrive, their aquarium water must be similar to the water in their natural environment. Poor water quality can cause stress, illness and even the loss of your fish. Important water quality parameters include ammonia, nitrite, nitrate, and pH. These can vary over time, and they are invisible to the eye, which is why it is necessary to test weekly. Choose from a wide range of API testing options like the Freshwater Master Test Kit or 5-in-1 Test Strips to accurately evaluate your water.

Pressed for Time? Just Dip and Read

Simply dip an API test strip into your aquarium, swirl it twice, and then use the color-coded chart to determine if your water is within safe parameters or if adjustments are needed. That’s it! API test strips are available in a 5-in-1 version, which includes testing for pH, nitrite, nitrate, carbonate, and general hardness. Ammonia and pH test strips are also available so you can mix and match according to your needs.

The Scientific Approach

Get professional results from the comfort of your home with API test kits. Measure up to six parameters with API Master Test Kits, or pick and choose from a wide variety of individual test kits. Both types of kits come with test tubes and a laminated, calibrated color card. API test kits allow for numerous tests, making them an inexpensive way to help keep your aquarium water quality in check.

How to Correct Aquarium Water Parameters

Too Much Ammonia?

Ammonia is released into the water through gills, urine, uneaten food and more. API Ammo-Lock detoxifies it instantly.

Inappropriate pH Levels?

Fish require a specific pH level to thrive. Use API pH Down to lower freshwater aquarium water pH to the right level.

Too Much Nitrite?

Use API Quick Start to quickly consume nitrite and help maintain an active biological filter.

Nitrates Too High?

API Nitra-Zorb helps remove nitrate and other toxins that can be harmful to fish and lead to algae growth.

About API

The team at API has a passion for fish and understands the rewards and relaxation fishkeeping can bring. For almost 60 years, they have developed premium products with a focus on proven and effective results. API offers a range of testing kits, water conditioners and nutritionally superior fish foods. They are dedicated to making a better underwater world for the benefit of fish and those who keep them.

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Fish TypeBetta, Bottom Feeder, Cichlid...Betta, Bottom Feeder, Cichlid...Betta, Cichlid, Goldfish, Marine Fish, Tropical FreshwaterMarine Fish, Tropical FreshwaterBottom Feeder, Discus, Goldfish, Marine Invertebrate
Aquarium TypeSaltwater, FreshwaterSaltwater, FreshwaterSaltwater, FreshwaterSaltwater, FreshwaterSaltwater, Freshwater, Pond

Questions & Answers

1 Customer Questions

I have a goldfish (8” with tail) whose tank is getting black spots on the tank glass and the plants are getting a dark color on them. How do I diagnose what is going on with the water?
Answer by ChewyNov 26, 2020
The easiest way to check your fish tank water is to buy a good all-round tester kit. The key things to look out for are ammonia, nitrite, nitrate, and pH. These compounds will be kept largely in check with a good mechanical, chemical, and biological filter.

ReviewsWrite a Review

Rated 4 out of 5 stars
4 Ratings
Would recommend to a friend

4 Customer Reviews

Rated 5 out of 5 stars
By Jdawg on Feb 4, 2022

A quick and easy way to gauge a critical water quality condition

I love these test strips for the simple reason that they measure perhaps the most deadly element in the hobby in a simple way. My only critique (and this is on me, not on API or Chewy,) is that I have a harder time reading these now than I did, say, 10 years ago. My eyesight being what it is, the subtleness of the distinctions in the color chart sometimes give me a tough time but usually just when trying to tell the difference between a straight 0 and somewhere between 0.5. I am confident that if there was a serious ammonia issue (which anything over 0 needs attention) the color would be telling as the green gets more intense. Lots of light and a white backdrop help with reading the results as well.

Rated 1 out of 5 stars
By Suncouch on Dec 7, 2021

False results

Strips have a weird setup of pad and plastic cover- couldn't get it to test right- after dipping it in water would either remain yellow on inside, blue around the edges, just yellow, or if I squeezed it, would turn blue. Led to a false sense of security when in reality was the cause of fish dying!

Rated 5 out of 5 stars
By Tricia on Feb 14, 2021

Works like it says

Fairly easy and accurate. I have 2 tanks and they read differently, so it's not like they're duds.

Rated 5 out of 5 stars
By Stormy on Jul 11, 2018

Easiest Ammonia Test Ever

Good product, fast, and easy to use -accurate reading