Why is Magnesium Chloride Hexahydrate Preferred Over Anhydrous Magnesium Chloride in Aquaculture and Livestock Farming?

Conclusion：

Magnesium chloride hexahydrate is widely used in aquaculture and livestock farming instead of anhydrous magnesium chloride, mainly for the following reasons:

I. Significant Cost Difference — Economic Priority

Magnesium chloride hexahydrate: Contains approximately 46% magnesium chloride flakes. The production process is relatively simple, with lower costs — even high-quality products cost only a few hundred RMB.

Anhydrous magnesium chloride: Content ≥98%, requiring additional dehydration and purification processes, with costs several times higher. Prices typically range from 2,600 to 8,000 RMB.

Farming scenario: Magnesium supplementation requires large quantities and is highly cost-sensitive. Magnesium chloride hexahydrate offers obvious cost-performance advantages.

II. Higher Safety — Avoiding Risks from Excessive Dosage

Safety is mainly reflected in two aspects:

On one hand, anhydrous magnesium chloride releases a large amount of heat when exposed to water, causing a sharp temperature rise and even boiling, which poses a risk of burns to operators. If anhydrous magnesium chloride is directly added to aquaculture water bodies, local high temperatures can cause severe stress to aquatic animals such as shrimp, crabs, and fish, and may even lead to death in severe cases.

On the other hand, since most anhydrous magnesium chloride is produced via the by-product process (titanium sponge by-product), some products may have excessive heavy metal content. Short-term feeding may not cause obvious symptoms, but long-term use carries the risk of heavy metal accumulation exceeding safety limits.

III. Easier to Use — Moderate Dissolution Rate

Magnesium chloride hexahydrate: Naturally contains 6 molecules of crystal water, dissolves at a moderate rate in water, and is easy to spread evenly.

Anhydrous magnesium chloride: Extremely hygroscopic and highly prone to caking. Must be used immediately after opening; storage and weighing are inconvenient.

Farming scenario: Most operations take place in open-air ponds or farms with high environmental humidity. Anhydrous magnesium chloride easily deliquesces and cakes, affecting usage efficiency.

IV. Matches Actual Demand — No Need for High Purity

Farming purpose: Supplement magnesium ions in water bodies or feed, regulate water hardness, promote algae growth, and enhance anti-stress capabilities.

Source of magnesium ions: Whether from hexahydrate or anhydrous form, both provide Mg²+ after dissolution, with essentially the same effect.

Conclusion: Farming does not require high purity above 98%. Magnesium chloride hexahydrate flakes with 46% content fully meet the requirements.

V. Easier to Meet Feed Grade / Aquaculture Grade Standards

Magnesium chloride hexahydrate: Relatively easy to purify from industrial grade to meet feed grade or aquaculture-specific standards (heavy metals, arsenic, lead, and other indicators are controllable).

Anhydrous magnesium chloride: Mostly high-end industrial grade products. Feed-grade anhydrous magnesium chloride specifically for the farming industry has limited supply and high prices.

VI. Easier to Control Dissolved Concentration

Magnesium chloride hexahydrate: Content is stable at around 46%, making it easy for farmers to calculate dosage and control magnesium ion concentration in water bodies.

Anhydrous magnesium chloride: High content but strong hygroscopicity; actual effective content is easily affected by storage conditions, making concentration control more difficult.

Special Case: When is Anhydrous Magnesium Chloride Used?

There is only one scenario: when a customer's technical R&D personnel have clear specifications and explicit parameter requirements for anhydrous magnesium chloride, our anhydrous magnesium chloride factory can produce customized batches. This type of custom production is relatively more expensive than standard mass-produced anhydrous magnesium chloride.

Yuze Summary Recommendations for Farming Magnesium Chloride Selection