Salifert Magnesium Test Kit

Salifert has been my personally preferred brand of test kit for the past 22+ years.

Manufacturer's description:

With the Salifert Magnesium Aquarium Test Kit, you can easily test the magnesium level in your tank. A favorite of discerning reefers for years, Salifert Aquarium Test Kits feature easy to read results.

• Accurate with measurements in steps of 30 mg/L
• Calcium and strontium will not interfere when their total concentration is between 200 and 650 ppm (this is usually the case)
• Precise color change, detecting small but significant fluctuations in the concentration of magnesium
• Sufficient for 50 tests