---
product_id: 441547021
title: "SEACHEM Laboratories Reef Advantage Magnesium 4kilo"
brand: "seachem"
price: "NZ$812"
currency: NZD
in_stock: true
reviews_count: 5
category: "Seachem"
url: https://www.desertcart.nz/products/441547021-seachem-laboratories-reef-advantage-magnesium-4kilo
store_origin: NZ
region: New Zealand
---

# SEACHEM Laboratories Reef Advantage Magnesium 4kilo

**Brand:** seachem
**Price:** NZ$812
**Availability:** ✅ In Stock

## Quick Answers

- **What is this?** SEACHEM Laboratories Reef Advantage Magnesium 4kilo by seachem
- **How much does it cost?** NZ$812 with free shipping
- **Is it available?** Yes, in stock and ready to ship
- **Where can I buy it?** [www.desertcart.nz](https://www.desertcart.nz/products/441547021-seachem-laboratories-reef-advantage-magnesium-4kilo)

## Best For

- seachem enthusiasts

## Why This Product

- Trusted seachem brand quality
- Free international shipping included
- Worldwide delivery with tracking
- 15-day hassle-free returns

## Description

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. DO NOT OVERDOSE: Excess magnesium may enhance the loss of carbonate alkalinity. Do not directly mix with any carbonate supplement. 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. Guaranteed Analysis: Magnesium (Mg) 8.00%

Review: Great supplement for your reef tank. - Great product, hands down! Dissolves quick and clear. Keeps my mag levels perfect. Definitely recommend.
Review: Good products - Good quality been using this for years

## Technical Specifications

| Specification | Value |
|---------------|-------|
| ASIN | B0002DGLR6 |
| Brand | Seachem |
| Brand Name | Seachem |
| Customer Reviews | 4.4 out of 5 stars 56 Reviews |
| Global Trade Identification Number | 00000116063906 |
| Item Form | Liquid |
| Item Weight | 4 Kilograms |
| Liquid Volume | 8.8 Litres |
| Manufacturer | Seachem |
| Manufacturer Part Number | 639 |
| Model Number | 639 |
| Target Species | Fish |
| UPC | 000116063906 |
| country-of-origin | USA |

## Product Details

- **Brand:** Seachem
- **Liquid Volume:** 8.8 Litres
- **Item Weight:** 4 Kilograms
- **Item Form:** Liquid
- **Manufacturer:** Seachem Laboratories, Inc.

## Images

![SEACHEM Laboratories Reef Advantage Magnesium 4kilo - Image 1](https://m.media-amazon.com/images/I/818qrSqXL0L.jpg)
![SEACHEM Laboratories Reef Advantage Magnesium 4kilo - Image 2](https://m.media-amazon.com/images/I/91-uAZ63PFL.jpg)

## Customer Reviews

### ⭐⭐⭐⭐⭐ Great supplement for your reef tank.
*by A***R on 13 August 2025*

Great product, hands down! Dissolves quick and clear. Keeps my mag levels perfect. Definitely recommend.

### ⭐⭐⭐⭐⭐ Good products
*by C***R on 9 January 2025*

Good quality been using this for years

### ⭐⭐⭐⭐⭐ Good deal container is cheap
*by G***R on 18 June 2026*

They went cheap on these buckets they are thin plastic did not ship well one of them actually cracked open a little and leaked in the Box not even a teaspoon worth but still who wants magnesium laying all over the place disappointed in the buckets

## Frequently Bought Together

- SEACHEM LABORATORIES Reef Advantage Magnesium 4kilo
- Reef Advantage Calcium, 4 kg / 8.8 lbs

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**Shop now:** [https://www.desertcart.nz/products/441547021-seachem-laboratories-reef-advantage-magnesium-4kilo](https://www.desertcart.nz/products/441547021-seachem-laboratories-reef-advantage-magnesium-4kilo)

---

*Product available on Desertcart New Zealand*
*Store origin: NZ*
*Last updated: 2026-08-05*