API Freshwater Master Test Kit vs Salifert Master Reef Testing Combo Kit

The API kit covers the full nitrogen cycle plus pH in liquid reagent form and costs very little per reading, which is why it is the default recommendation for freshwater tanks. The Salifert combo is the better answer once corals are involved, because reef chemistry needs finer steps on alkalinity, calcium and magnesium than any freshwater color card provides.

API Freshwater Master Test Kit

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Liquid reagents for the five numbers that decide whether a freshwater tank is safe, at a cost per test almost nothing else matches.

• Covers pH, high range pH, ammonia, nitrite and nitrate, which is the whole nitrogen cycle plus the pH you need to interpret it
• The box states over 800 tests and includes seven reagent bottles, test tubes, a holding tray and a laminated color card
• Liquid reagents in glass tubes give a far more readable color than a pad on a paper strip

• Freshwater only, with no saltwater color card in this kit
• Does not include GH, KH or phosphate, which buyers frequently assume a master kit covers
• The nitrate test is technique sensitive, requiring a 30 second shake of Solution #2 and a full minute of shaking the capped tube

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Salifert Master Reef Testing Combo Kit

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Six single-parameter reef kits in one box, with the resolution on alkalinity and calcium that coral dosing actually requires.

• Bundles calcium, KH/alkalinity, magnesium, nitrate, phosphate and pH, which is the working set for a reef tank
• Reads in fine steps: about 0.3 dKH on alkalinity, 10 mg/L on calcium and 30 mg/L on magnesium
• Boxes are replaced individually, so you rebuy only the parameter you actually used up

• No ammonia and no nitrite test in the combo, so a cycling tank needs Salifert's separate ammonia kit or another source
• Test counts vary widely by parameter, from about 50 on magnesium and pH up to 100 to 200 on alkalinity
• Salifert lists its Profi-Test line under reef and marine, with the freshwater section on its own site still unbuilt

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Side by side

The bottom line

Our overall pick is the API Freshwater Master Test Kit - Liquid reagents for the five numbers that decide whether a freshwater tank is safe, at a cost per test almost nothing else matches. Choose the Salifert Master Reef Testing Combo Kit instead if reef keepers dosing calcium and alkalinity who want tight readings without buying a meter for every parameter.

Want the full picture, including the other options we compared and the popular one we'd skip? Read the complete The Best Aquarium Water Test Kits: 4 Compared (and One to Skip).