Salifert Magnesium Aquarium Test Kit
SKU: SF-MAPT
- The Salifert Magnesium Aquarium Test is a titration-based magnesium test kit for reef and saltwater aquariums.
- It measures magnesium in 30 mg/L increments with a sharp color change endpoint that makes results easy to read confidently.
- Each kit contains reagents for approximately 50 tests.
- Results are reported in mg/L (ppm), the standard unit for magnesium in reef chemistry.
Salifert
Precision test kits trusted by reefers worldwide. Known for accurate, easy-to-read results for all critical reef and freshwater parameters.
Magnesium Test Kit for Reef and Saltwater Aquariums
The Salifert Magnesium Profi-Test is a titration-based test kit for measuring magnesium concentration in marine aquariums. Magnesium is the third pillar of the calcium/alkalinity/magnesium triad that drives coral skeletal growth, and it plays a role that is often underappreciated until something starts going wrong. Natural seawater contains 1,300–1,400 mg/L of magnesium, and keeping reef tank levels in that range is not just about coral nutrition — magnesium actively suppresses the spontaneous precipitation of calcium carbonate in the water column. When magnesium drops too low, calcium and alkalinity begin to deplete faster than expected, dosing math stops working, and no amount of two-part or calcium reactor adjustment will fully compensate until magnesium is corrected first.
Salifert's magnesium test measures in 30 mg/L increments with a distinct, sharp color change that makes the endpoint easy to identify without ambiguous interpretation. The kit is formulated to avoid interference from calcium and strontium within normal reef ranges, keeping results reliable across a range of tank chemistries. Each kit yields approximately 50 tests.
Key Features:
- Titration-based test with a sharp, clear color change endpoint for confident result reading.
- Measures in 30 mg/L increments across the full reef-relevant range (750–1,500 mg/L).
- Formulated to resist interference from calcium and strontium within normal aquarium bounds.
- Approximately 50 tests per kit.
- Trusted by reef hobbyists for consistent performance across saltwater and reef applications.
Ideal For:
- Reef tanks where unexplained calcium or alkalinity depletion may indicate a low magnesium problem.
- Hobbyists running two-part dosing, calcium reactors, or kalkwasser who test the full triad on a regular schedule.
- Any saltwater tank keeper who wants to verify magnesium is in the natural seawater range before troubleshooting other parameter drift.
Why Magnesium Matters?
Magnesium is present in natural seawater at 1,300–1,400 mg/L — roughly three times the concentration of calcium. In a reef tank, its most critical function is chemical: magnesium slows the spontaneous formation of calcium carbonate in the water column. Without sufficient magnesium, calcium and carbonates combine abiotically (outside of coral tissue), forming a white precipitate that depletes both calcium and alkalinity without contributing anything to coral growth. The lower the magnesium, the faster and more aggressively this process occurs, and the harder it becomes to maintain stable calcium and alkalinity regardless of dosing strategy. Correcting magnesium first is often the key to unlocking stability in tanks where calcium and alkalinity seem impossible to keep in range.
Pro Tips:
- Test magnesium monthly in stable systems, more often when troubleshooting. Unlike calcium and alkalinity, magnesium changes slowly in most reef tanks. Monthly testing is sufficient for maintenance, but if your calcium or alkalinity is dropping faster than your dosing math predicts, test magnesium immediately — it's frequently the culprit.
- Raise magnesium slowly when correcting a deficit. Large, rapid magnesium swings can stress corals and invertebrates. If you're correcting a significant deficit, aim to raise levels by no more than 100–150 mg/L per day until you reach your target.
- Store reagents away from heat and light. As with all Salifert test kits, reagent degradation is the most common source of inconsistent results. Keep the kit in a cabinet or drawer, not on the tank stand or in direct light.
What's Included:
- Magnesium Profi-Test reagents
- Syringe/titrant
- Test vial
Specifications:
- Test Method: Titration
- Parameter Measured: Magnesium (Mg)
- Unit of Measurement: mg/L (ppm)
- Measurement Increments: 30 mg/L
- Measurement Range: 750–1,500 mg/L
- Recommended Range: 1,300–1,400 mg/L (natural seawater)
- Number of Tests: ~50
- Application: Saltwater / reef aquariums
While most of our equipment carries a one-year manufacturer's warranty, consumable products like fish and coral foods are not covered under traditional warranty terms due to their perishable nature and varied storage conditions. However, we fully stand behind the quality of every product we sell. If you experience any issues with your food purchase shortly after receiving it, such as concerns about freshness, packaging integrity, or product quality, please contact us at [email protected]. We're committed to making it right and will work with you to resolve any problems quickly and fairly.
For best results, follow the instructions included with your kit. Salifert's step-by-step guide is printed for your specific reagent batch and is the most reliable reference for accurate testing.