The best aquarium water test kits & treatments (2026)
You cannot manage what you do not measure. We compare liquid test kits (far more accurate than strips), water conditioners and bacteria starters so you can cycle a new tank safely and keep an established one stable.
API · liquid · pH/ammonia/nitrite/nitrate · 800 tests
Freshwater Master Test Kit
The default liquid test kit for freshwater keepers: pH, ammonia, nitrite and nitrate in one box, far more accurate than strips and cheap per test across ~800 readings.
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SEACHEM · conditioner · dechlorinator · 500 mL / ~5000 L
Prime
The most concentrated dechlorinator on the shelf: removes chlorine and chloramine, detoxifies ammonia and nitrite, and doses at just 5 mL per 200 L — one small bottle lasts months.
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JBL · liquid case · pH/KH/NO2/NO3/NH4/CO2 · refillable
ProAquaTest Combi Set Plus NH4
JBL's carry-case liquid test set: pH, carbonate hardness, nitrite, nitrate and ammonium in one refillable box, with a CO2 table thrown in — the go-to master set on European Amazon.
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API · liquid titration · GH + KH · dual bottles
GH & KH Test Kit
The liquid drop-count kit for the two hardness numbers the master kit leaves out: general hardness (GH) and carbonate hardness (KH). Cheap, accurate and essential for shrimp, plants and pH stability.
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DR TIM'S AQUATICS · bacteria starter · live nitrifiers · 32 oz / ~480 US gal
One & Only Nitrifying Bacteria (Freshwater)
Live nitrifying bacteria that seed a new filter fast — the go-to bottle for a fish-in or fishless cycle. Refrigerated, single-species nitrifiers that many keepers trust over shelf-stable rivals.
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SEACHEM · bottled bacteria · fresh + marine · 100 mL
Stability
Seachem's bottled bacteria for seeding a new filter fast. A blend of aerobic and anaerobic species that will not produce toxic hydrogen sulphide, works in fresh or salt, and does not need refrigerating.
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API · liquid · ammonia only · 130 tests · 0–8 ppm
Ammonia Test Kit
A dedicated liquid ammonia test — the single most important reading when cycling or after a fish loss. Cheap, accurate and a natural top-up when your master kit's ammonia bottles run dry.
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API · conditioner + aloe vera · 237 mL / ~1800 L
Stress Coat
A dechlorinator with a twist: it removes chlorine and chloramine like any conditioner, then adds aloe vera to protect and rebuild the fish's slime coat — handy for new arrivals, transport and minor injuries.
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TETRA · dip strips · 6 parameters · 100 count
EasyStrips 6-in-1
Dip-and-read strips for a fast weekly glance at six parameters — nitrate, nitrite, GH, KH, chlorine and pH. Convenient and cheap per box, but coarser than a liquid kit and missing ammonia.
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API · strips · pH/KH/GH/NO2/NO3 · 25-count
5-in-1 Test Strips
Dip-and-read strips that give five readings in a minute: pH, KH, GH, nitrite and nitrate. Convenient for a fast weekly glance — just not as accurate as a liquid kit.
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