Seachem Reef Advantage – Magnesium
Reef Advantage Magnesium is a concentrated (80,000 ppm) optimized blend of magnesium, chloride, and sulfate salts designed to restore depleted levels of magnesium with minimal impact to the ionic ratios found in natural sea water.
Reef Advantage Magnesium contains no ammonia!
This is a common contaminant in every liquid magnesium supplement on the market. Severely depleted levels of magnesium (below 800 mg/L) can cause depressed pH levels and an inability to maintain proper calcium levels.
Magnesium depletion is commonly associated with the use of kalkwasser.
Directions
- Beginner: Use 1 level teaspoon per 80 L (20 gallons*) twice a week. Dissolve in at least one cup of freshwater.
- Advanced: Check magnesium levels regularly and adjust dosage as needed based on test results.
| Component | Concentration |
|---|---|
| Magnesium | 80,000 ppm |
| Chloride | Optimized blend |
| Sulfate | Optimized blend |
FAQ
Is Reef Advantage Magnesium safe for use in reef tanks with sensitive corals?
Yes, Reef Advantage Magnesium is formulated to maintain stable ionic ratios and is safe for use in reef tanks with sensitive corals due to its optimized blend and absence of ammonia.
How often should I add Reef Advantage Magnesium to my tank?
Beginners should use 1 level teaspoon per 80 L (20 gallons) twice a week. Advanced users should monitor magnesium levels and adjust dosage accordingly.
Can I use this product if I already use kalkwasser in my tank?
Yes, magnesium depletion is commonly linked to kalkwasser use. This product helps restore magnesium levels without disrupting the ionic balance.



Audrey Welch –
I’ve been using Reef Advantage Magnesium for three months now. My tank’s magnesium levels have stabilized and my corals are showing better coloration. No ammonia detected, which is a relief after trying other brands. Easy to measure and mix.
Diane Gibson –
The product works well for maintaining magnesium levels. I use it twice a week as recommended. My pH has stayed stable, and I haven’t had any issues with calcium balance. A reliable supplement for reef tanks.
Nathan Jackson –
After switching from a generic magnesium supplement, I noticed a significant improvement in coral health. The absence of ammonia is a major plus. It’s easy to dose and integrates smoothly into my routine.