Seachem Reef Advantage Magnesium 4 Kg

Seachem Reef Advantage Magnesium is a concentrated, ionically balanced magnesium source that’s ammonia-free and vital for preventing ionic imbalance.

• Concentrated, blended, ionically balanced magnesium source.
• Contains NO Ammonia.
• Vitally important in preventing ionic imbalance.

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 magnesium 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 redissolve. Magnesium carbonate will redissolve; however, it does so slowly. So, while it will go back into solution, there will be a significant portion of time in which magnesium levels are depleted.

The Seachem Reef Advantage Magnesium 4 Kg corrects magnesium, which keeps calcium and KH stable in a reef tank — see our guide to Calcium & Magnesium for how the three interact.

Freshness & Storage

Every batch we dispatch carries a minimum of 6 months' remaining shelf life. Store this product in a cool, dry place away from direct sunlight, with the cap or inner foil closed tightly after each use.

Returns & Replacement

Returns are accepted within 7 days of delivery, provided the item is unused and in its original packaging. Manufacturer-sealed items cannot be returned once the seal is broken, and sale-priced items are not refundable.

If your item arrives defective or damaged, message us on WhatsApp with your order number — or email us, if you would rather — and we will replace it. Approved replacements are delivered within 3 to 5 business days. Transit damage is covered by insurance on every shipment. If tracking shows delivered but nothing reached you, tell us within 72 hours, which is the reporting window Indian couriers allow. Damage caused during installation or use is not covered; replacement spares for such cases are chargeable.

Full terms are on our Cancellation & Returns page.