Top 10 Aquarium Test Kits for Monitoring Ammonia and Nitrite in 2027

By Kory White · Updated Oct 2026 · 5 min read

Direct answer

The Hanna Instruments HI707 Nitrite Low Range Checker HC (£90.12 including VAT) is the best nitrite tester here, a digital meter reading 0 to 600 ppb in freshwater and saltwater. The Hanna HI700 ammonia checker is #2 and the Tropic Marin NH4+/NH3 test, reading down to 0.02 mg/l, is #3.

At a glance

#	Pick	Test type	Best for
1	Hanna Instruments HI707 Nitrite Low Range Checker HC	Handheld digital colorimeter (photometer)	A digital nitrite reading in either freshwater or a reef tank
2	Hanna Instruments HI700 Ammonia Low Range Checker HC	Handheld digital colorimeter (photometer)	Freshwater keepers who want a digital ammonia number
3	Tropic Marin NH4+/NH3 Ammonium/Ammonia Test	Liquid colour-comparison kit	The finest published resolution of any liquid ammonia kit here
4	Red Sea Ammonia Marine Test Kit	Liquid colorimetric kit	New reef tanks cycling for the first time
5	Red Sea Nitrate/Nitrite Marine Test Kit	Liquid colorimetric kit	Reef keepers who want nitrite and nitrate in one kit
6	API Ammonia Test Kit	Liquid dropper kit	A widely stocked ammonia test for fresh or salt water
7	API Nitrite NO2 Test Kit	Liquid test kit	Watching nitrite spikes during a new tank cycle
8	Seachem Ammonia Alert	Continuous color-changing sensor badge	An always-visible warning of free ammonia with no testing
9	Seneye Home V6	Continuous monitor with replaceable slides	Round-the-clock free ammonia logging alongside pH and temperature
10	Tetra EasyStrips Ammonia Test Strips	Dip-and-read test strips	A quick ammonia check with no vial or reagents

Pick by what you want

Best digital nitrite reading

Hanna Instruments HI707 Nitrite Low Range Checker HC

Best digital ammonia reading (freshwater)

Hanna Instruments HI700 Ammonia Low Range Checker HC

Most sensitive liquid ammonia kit

Tropic Marin NH4+/NH3 Ammonium/Ammonia Test

Best for a new reef cycle

Red Sea Ammonia Marine Test Kit

Widest ammonia range

API Ammonia Test Kit

Best always-on warning

Seachem Ammonia Alert

Best continuous monitor

Seneye Home V6

Fastest check

Tetra EasyStrips Ammonia Test Strips

The ranking

Hanna Instruments HI707 Nitrite Low Range Checker HC

Answrs VerdictThe only meter here that reads nitrite digitally for both water types.

Test type: Handheld digital colorimeter (photometer)Range: 0 to 600 ppb NO2-N, 1 ppb resolutionAccuracy: ±20 ppb ±5% of reading at 25°CWater type: Freshwater and saltwater aquariumsTests: Starter reagent kit covers 6 tests; the HI-707-25 refill pack covers 25Price: £90.12 including VAT (£75.10 excluding VAT), Hanna UK

The HI707 is a handheld digital colorimeter that reads nitrite from 0 to 600 ppb NO2-N with 1 ppb resolution and ±20 ppb ±5% accuracy. Hanna says it suits freshwater and saltwater aquariums. The starter reagent kit covers 6 tests and a 25-test refill is sold. It costs £90.12 including VAT.

Go ifA digital nitrite reading in either freshwater or a reef tank

Skip ifYou want a cheap kit with many tests per purchase

Why #1 over #2: It reads nitrite to 1 ppb resolution, where the API Nitrite kit lists a 0 to 5 ppm color scale.

Hanna Instruments HI700 Ammonia Low Range Checker HC

Answrs VerdictA digital ammonia reading, but Hanna lists it for fresh water only.

Test type: Handheld digital colorimeter (photometer)Range: 0.00 to 3.00 ppmAccuracy: ±0.05 ppm ±5% of readingWater type: Hanna UK calls it ideal for fresh water aquariums and makes no marine claimTests: The HI-700-25 starter reagent kit covers 25 testsPrice: £90.12 including VAT (£75.10 excluding VAT), Hanna UK

The HI700 reads ammonia from 0.00 to 3.00 ppm with ±0.05 ppm ±5% accuracy, and its starter reagent kit covers 25 tests. Hanna UK calls it ideal for fresh water aquariums and says nothing about saltwater. It costs £90.12 including VAT.

Go ifFreshwater keepers who want a digital ammonia number

Skip ifYou keep a saltwater tank

Why #2 over #3: Its ±0.05 ppm accuracy is tighter than the 0.2 ppm Red Sea lists, but it is freshwater only.

Tropic Marin NH4+/NH3 Ammonium/Ammonia Test

Answrs VerdictThe most sensitive liquid kit, reading down to 0.02 mg/l.

Test type: Liquid colour-comparison kitRange: 0.02 to 3.0 mg/l (ppm)Accuracy: 0.03 mg/l (ppm)Water type: Freshwater and saltwater aquariaKit contents: Reagents A, B and C, a 10 ml glass cuvette, a 5 ml dosing syringe, two colour cardsPrice: Not published

This liquid colour-comparison kit reads total ammonium and ammonia from 0.02 to 3.0 mg/l with 0.03 mg/l accuracy, in freshwater and saltwater. It includes reagents A, B and C, a 10 ml glass cuvette, a 5 ml dosing syringe and two colour cards. Tropic Marin lists no price.

Go ifThe finest published resolution of any liquid ammonia kit here

Skip ifYou need a published price or test count before buying

Why #3 over #4: Its 0.03 mg/l accuracy beats the 0.2 ppm of the Red Sea ammonia kit.

Red Sea Ammonia Marine Test Kit

Answrs VerdictA 100-test marine kit built for the first cycle.

Test type: Liquid colorimetric kitRange: 0-2 ppm total ammonia (NH3/NH4)Accuracy: 0.2 ppmTests: 100 testsWater type: Marine and reef aquariumsPrice: Not published

Red Sea’s kit is a colorimetric test for total ammonia (NH3/NH4) from 0-2 ppm with 0.2 ppm accuracy and 100 tests, made for marine and reef aquariums. Red Sea lists no price.

Go ifNew reef tanks cycling for the first time

Skip ifYou keep a freshwater tank

Why #4 over #5: It gives 100 tests, and the API ammonia listing gives no test count.

Red Sea Nitrate/Nitrite Marine Test Kit

Answrs VerdictNitrite accurate to 0.05 ppm in a marine kit.

Test type: Liquid colorimetric kitNitrite range: 0-1 ppm, accuracy 0.05 ppmTests: 50 nitrate and 50 nitrite tests, or 100 nitrite tests aloneNitrate range: 0-250 ppm, accuracy 2 ppmWater type: Marine aquariumsPrice: Not published

This marine kit tests nitrite from 0-1 ppm with 0.05 ppm accuracy and nitrate from 0-250 ppm with 2 ppm accuracy. It provides 50 nitrate and 50 nitrite tests, or 100 nitrite tests alone. Red Sea lists no price.

Go ifReef keepers who want nitrite and nitrate in one kit

Skip ifYou only need freshwater nitrite

Why #5 over #6: Its 0.05 ppm nitrite accuracy is a figure the API Nitrite listing does not give.

API Ammonia Test Kit

Answrs VerdictThe widest ammonia range here, 0 to 8 ppm, for both water types.

Test type: Liquid dropper kitRange: 0 to 8 ppm ammoniaWater type: Freshwater and saltwater aquariumsMethod: 8 drops from each of two bottles in a 5 ml sample, then a 5-minute waitKit contents: Two dropper bottles, instructions, two color charts and a test tube with a snap-tight capPrice: Not published

API’s liquid dropper kit reads ammonia from 0 to 8 ppm in freshwater and saltwater aquariums. You add 8 drops from each of two bottles to a 5 ml sample and wait 5 minutes. API lists no price.

Go ifA widely stocked ammonia test for fresh or salt water

Skip ifYou want a published accuracy figure

Why #6 over #7: Its 0 to 8 ppm scale is wider than the Seachem badge’s top level of about 0.5 mg/L.

API Nitrite NO2 Test Kit

Answrs VerdictA simple nitrite test that covers fresh and salt water.

Test type: Liquid test kitRange: 0 to 5 ppm nitriteWater type: Freshwater and saltwater aquariumsPackage size: 1 CTPrice: Not published

The API Nitrite NO2 Test Kit tests nitrite from 0 to 5 ppm and can be used in freshwater and saltwater aquariums. The page lists the size as 1 CT and gives no price.

Go ifWatching nitrite spikes during a new tank cycle

Skip ifYou need a published test count

Why #7 over #8: It covers 0 to 5 ppm nitrite, while the Tetra strips test ammonia only.

Seachem Ammonia Alert

Answrs VerdictA year-long badge that watches free ammonia for you.

Test type: Continuous color-changing sensor badgeAlert levels: Safe below 0.02 mg/L, alert about 0.05 mg/L, alarm about 0.2 mg/L, toxic about 0.5 mg/L free ammoniaResponse: About 15 minutes to rising ammonia; about 4 hours to return to safeLifespan: Over a yearWater type: Freshwater and marinePrice: Not published

Ammonia Alert is a small color-changing sensor that shifts from yellow to green to blue as free ammonia rises: safe below 0.02 mg/L, alert about 0.05 mg/L, alarm about 0.2 mg/L and toxic about 0.5 mg/L. It responds in about 15 minutes, lasts over a year and works in freshwater and marine tanks. Seachem lists no price.

Go ifAn always-visible warning of free ammonia with no testing

Skip ifYou need a numeric reading or nitrite

Why #8 over #9: It needs no testing at all, unlike the Seneye Home V6 which relies on slides and costs $186.00 USD.

Seneye Home V6

Answrs VerdictThe only continuous multi-parameter monitor here, but it does not list nitrite.

Test type: Continuous monitor with replaceable slidesMeasures: Temperature, free ammonia (NH3), pH, total light and water levelWater type: All aquariums: coldwater, tropical and marineSlides: seneye+ Flat Mail Pack Slides (x3) are $38.99Price: $186.00 USD

The Seneye Home V6 monitors temperature, free ammonia (NH3), pH, total light and water level in coldwater, tropical and marine aquariums. It costs $186.00 USD, and three replacement slides are $38.99. Some features need a seneye+ subscription.

Go ifRound-the-clock free ammonia logging alongside pH and temperature

Skip ifYou need a nitrite reading

Why #9 over #10: It logs five parameters, where the Tetra strips test ammonia only.

Tetra EasyStrips Ammonia Test Strips

Answrs VerdictThe fastest check here, at roughly 10 seconds.

Test type: Dip-and-read test stripsDetects: Ammonia onlyResult time: About 10 seconds of dipping, then compare to the color chartPack sizes: 25 ct and 100 ctPrice: Not published

These dip-and-read strips test only for ammonia: swish for about 10 seconds and compare to the color chart. They come in 25 ct and 100 ct packs, and Tetra lists no price.

Go ifA quick ammonia check with no vial or reagents

Skip ifYou need a numeric, precise reading

How we ranked these

We ranked each product on how precisely its maker lists the reading (digital meters first, then liquid kits by published accuracy, then continuous monitors and strips), then on range, water types covered and ease of use. Every figure comes from the maker’s own page. Where the maker publishes no price we say so. Facts are taken from each maker's own published information; check the official site before you buy.

Questions people ask

What is the best ammonia and nitrite test kit for an aquarium?

The Hanna Instruments HI707 Nitrite Low Range Checker HC reads nitrite digitally from 0 to 600 ppb in freshwater and saltwater, at £90.12 including VAT. For ammonia, the Tropic Marin NH4+/NH3 test reads down to 0.02 mg/l.

Which test kit measures the widest ammonia range?

The API Ammonia Test Kit reads 0 to 8 ppm and is made for freshwater and saltwater aquariums.

Is there a test that watches ammonia continuously?

Yes. The Seachem Ammonia Alert is a color-changing badge that lasts over a year, and the Seneye Home V6 ($186.00 USD) monitors free ammonia, pH, temperature, light and water level.

Can I use the Hanna HI700 ammonia checker in a saltwater tank?

Hanna UK describes the HI700 as ideal for fresh water aquariums and makes no marine claim, so use a marine-listed kit such as the Red Sea Ammonia Marine Test Kit for a reef tank.

Top of the measuring range at a glance

Red Sea Nitrate/Nitrite (nitrite)1 ppm

Red Sea Ammonia Marine Test Kit2 ppm

Hanna HI700 Ammonia LR3 ppm

Tropic Marin NH4+/NH3 Test3 ppm

API Nitrite NO2 Test Kit5 ppm

API Ammonia Test Kit8 ppm

Top of the measuring range, as published by each maker. Picks without a published figure are left off.

Official sites

Hanna Instruments HI707 Nitrite Low Range Checker HC · hannainstruments.co.uk
Hanna Instruments HI700 Ammonia Low Range Checker HC · hannainstruments.co.uk
Tropic Marin NH4+/NH3 Ammonium/Ammonia Test · calulator.tropic-marin.com
Red Sea Ammonia Marine Test Kit · redseafish.com
Red Sea Nitrate/Nitrite Marine Test Kit · redseafish.com
API Ammonia Test Kit · apifishcare.com
API Nitrite NO2 Test Kit · apifishcare.com
Seachem Ammonia Alert · seachem.com
Seneye Home V6 · seneye.com
Tetra EasyStrips Ammonia Test Strips · tetra-fish.com

Prices, specs and availability change; confirm on the official site before you buy.