Seachem Reef Advantage Magnesium is a concentrated blend of magnesium, chloride and sulfate salt designed to restore depleted levels of magnesium with minimal impact on the ionic ratios found in natural seawater. Unlike other liquid magnesium supplements, Reef Advantage Magnesium contains no ammonia! 600 grams treats 2,500 gallons.

Beginner: Use 1 level teaspoon per 20 gallons twice a week. Dissolve in at least one cup of freshwater.

Advanced: Check magnesium level, then follow dosing regimen above until magnesium is adjusted to 1200-1350 mg/L. Each dose will raise magnesium by about 5 mg/L. Size or frequency of dose can be adjusted, but do not exceed 25 mg/L per day. Thereafter, use as required to maintain magnesium.

Expert: After determining the magnesium depletion rate, set up a continuous drip system. Use the following formula to determine how much to add to your top-off water:

t=0.01vm
t=teaspoons to add to top off water, v=volume of tank in gallons, m=amount to raise magnesium in mg/L).

For example, if you want to raise magnesium by 10 mg/L in a 50 gallon tank, then you would add 0.01x50x10=5 teaspoons into the top-off water.

Do not Overdose: Excess magnesium may enhance the loss of carbonate alkalinity. Do not directly mix with any carbonate supplement. It is best if magnesium & carbonate additives are added on alternate days or at least 30 minutes apart. Slight clumping of this product may be encountered but does not impact its use; any clumps will break up very easily.

General Information

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.

Why It's Different
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. The most frequent causes of magnesium deficiency are use of kalkwasser, frequent overdosing of a carbonate additive, or low levels in the salt mix itself. Kalkwasser, for instance, precipitates magnesium as magnesium hydroxide while excess carbonates precipitate it as magnesium carbonate. In both cases, this means that magnesium that was present in the water is now unavailable. Of the two, magnesium hydroxide and magnesium carbonate, the former is more problematic; it is extremely insoluble. Once magnesium has precipitated as magnesium hydroxide, it will never re-dissolve. Magnesium carbonate will re-dissolve slowly. So, while it will go back into solution, there will be a significant portion of time in which magnesium levels are depleted.