Brightwell Aquatics Magnesion-P
Overview
- High-purity, anhydrous powdered magnesium blend
- Provides magnesium to regulate the balance between calcium and carbonates in aquarium water; a component of aragonite, the mineral secreted by reef-building organisms such as corals, clams, and their allies to form skeletal material
- Contains about 300% the magnesium of almost all other products on the market due to its anhydrous (water-free) formulation
- Free from unwanted organic materials such as EDTA, gluconate, or polygluconate
- Formulated by a marine scientist
Technical Background
Magnesium plays a vital role in reef aquaria: it helps maintain stable water chemistry by supporting the equilibrium between calcium and carbonates, which is essential for the growth and health of reef-building organisms.
| Specification | Value |
|---|---|
| Magnesium Content | 300% higher than most market alternatives |
| Formulation Type | Anhydrous powder |
| Organic Additives | None (EDTA, gluconate, polygluconate absent) |
| Formulator | Marine scientist |
FAQ
What makes Magnesion-P different from other magnesium products?
Magnesion-P is anhydrous, meaning it contains no water, which allows it to deliver up to 300% more magnesium than most other products on the market. It also excludes organic additives like EDTA or gluconate, which can interfere with water chemistry.
How does magnesium affect reef aquariums?
Magnesium helps maintain the balance between calcium and carbonates in aquarium water. This balance is essential for the formation of aragonite, the mineral used by corals, clams, and other reef organisms to build their skeletons.
Is Magnesion-P safe for all types of aquariums?
Yes, Magnesion-P is specifically formulated for reef aquariums and is safe for use in marine environments where stable water chemistry is required.

Hannah Oliver –
I’ve used Magnesion-P for three months now and noticed a significant improvement in my coral growth. The water chemistry has stabilized, and my polyps are more active than before. No signs of cloudiness or imbalance. Highly recommend for reef keepers.
Dominic Tucker –
The magnesium levels in my tank have remained consistent without any spikes or drops. I appreciate that it’s free from organic additives, which I’ve read can cause long-term issues in reef systems. Easy to measure and mix.
Emma Skinner –
It works well in my 120-gallon reef tank. The magnesium levels stay steady, and I haven’t had any issues with calcium or carbonate imbalances. A bit more expensive than other brands, but the quality justifies the price.