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Brightwell Aquatics Magnesion - Liquid Magnesium Supplement for Reef Aquaria 250mL / 8.5oz


Item #: BW01037

In Stock

• Highly-concentrated ionic magnesium solution.

• Provides magnesium, which helps regulate the balance between calcium and carbonates in aquarium

water, and is a component of aragonite, the mineral secreted by reef-building organisms such as corals,

clams, and their allies to form skeletal material.

• Stronger than most competing products.

• Contains no unwanted organic material such as EDTA, gluconate, or polygluconate.

• Formulated by a marine scientist.

  • Liquid
  • 250-ml

Reef Chemistry Calculator

Use our chemistry calculator to find out how much you need to add to your aquarium.

Manufacturer information

Brightwell Aquatics Aquarium Supplies
The goal of Brightwell Aquatics is to provide the absolute highest quality, scientifically-sound products and customer service of any aquarium water care manufacturer, and to do it all in a straight-forward and honorable fashion. All Brightwell products are formulated by marine scientists with a passion for the aquarium hobby. They utilize the highest purity ingredients in concentrations that provide the most use to hobbyists. Nearly all Brightwell Aquatics products are over 99.9% pure. The usage guidelines of Brightwell Aquatics products are written in plain language but the company is always available to answer consumer questions. All products are lot numbered for quality control and customer service.

5 Stars


Reviewed on
September 23, 2020

Yes, I would recommend this.

good product

I've been using it for a long time, it keeps my mg stable and it's very good

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Reviewed on
June 15, 2020

Yes, I would recommend this.

Products and services

Pros: Super merchandise

Cons: Can’t see faces

Everyone at MarineDepot is top of the line professionals. Love them all. All my products come from Marine Depot

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Reviewed on
May 07, 2020

Yes, I would recommend this.

Brightwell Aquatics Magnesion

Pros: great price great product

Cons: none

works as described dependable been dosing with brightwell for years

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Reviewed on
March 28, 2019

Yes, I would recommend this.

Works well

Pros: Works well

Cons: None

Helps keep my magnesium parameters stable. Works well work great results, would recommend.

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Reviewed on
June 26, 2017

Yes, I would recommend this.

Best Mag out there

I love Brightwell Aquatics Magnesium. I've been using it for over a decade now and wouldn't switch for anything. Brightwell makes incredible products, and amazing quality.

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Reviewed on
June 09, 2017

Yes, I would recommend this.


Pros: Good product, good price

Cons: None

Brightwell products are very high quality and Marine Depot has them for great prices.

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james garner

Reviewed on
March 23, 2016

No, I would not recommend this.

Diluted and weak.

This stuff must be water. Have to dose excessive amounts just to get my Mg up a little. I test every day and my levels have not increased much. I know better than this. I used to use SeaChem's Magnesium and never had any trouble raising my Mg level. I see a lot of you praising this garbage, but I won't ever buy it again. Pure Water!

Was this review helpful? 0 8

karen martinsen

Reviewed on
February 06, 2014

Yes, I would recommend this.

magnesium great

I only use Bright well products, there all compatible with each other in my reef 40 gal. I only use Reef code A and B, Snow, and Magnesium. Also throw in the refegium a chemi-pure elite, corals are happy, my 2 clowns. There going on 3 years of age.

Was this review helpful? 1 0

bing sherer

Reviewed on
June 30, 2013

Yes, I would recommend this.

Good Stuff

8 ml per day keeps my 150 reef/fish set up at the correct level. Been using Brightwell products since initial setup in 2009

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wing cheng

Reviewed on
July 09, 2012

Yes, I would recommend this.

great product

I dose to my tank as instructed. The quality of water is now getting healthier.

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