Reef Fusion 2 4 L — Alkalinity 4400 meq/L 2-Part System | Seachem

Seachem Reef Fusion 2 in a 4L bottle is an alkalinity supplement based on a concentrated blend of carbonates and bicarbonates (4400 meq/L), designed to restore and maintain alkalinity in reef aquariums. Part of the Reef Fusion system—the most concentrated 2-part system on the market—it is dosed in a 1:1 ratio with Seachem Reef Fusion 1 (calcium). The 4L size is the most economical choice in the range, ideal for large reef aquariums and long-term automated dosing.

Main advantages

• Concentration of 4400 meq/L — the most concentrated 2-part system available
• 4L size — the most economical in the Reef Fusion range for large systems
• Provides the carbonates essential for the growth of calcareous species
• Simple 1:1 dosing ratio with Reef Fusion 1
• Compatible with dosing pumps for automated long-term maintenance

Use in reef aquariums

Alkalinity is essential for coral skeleton formation and pH stability. The Reef Fusion system offers a complete solution: Reef Fusion 1 provides 100,000 mg/L of ionic calcium with magnesium, strontium, boron, iron, manganese, and molybdenum, while Reef Fusion 2 provides carbonate alkalinity at 4,400 meq/L. Together, they maintain critical calcium and alkalinity levels while supplying biologically appropriate trace elements.

Dosage

• Dose every 1 to 2 days. Shake well before use.
• Add 1 ml of Reef Fusion 1 per 25 L (6.5 US gallons) in a high-current area. Wait a few minutes, then add 1 ml of Reef Fusion 2 per 25 L.
• Each dose provides 4 mg/L of calcium and 0.176 meq/L of alkalinity.
• Maintain calcium between 380 and 420 mg/L and alkalinity between 3 and 6 meq/L (8–17 dKH).
• Do not exceed 4 ml per 25 L per day.

Manufacturer's precautions

• Never mix Reef Fusion 1 directly with Reef Fusion 2
• Add the two products to separate locations in the aquarium.
• Make significant adjustments gradually to avoid shocking the corals and invertebrates.

Available formats

• 500 ml
• 1 L
• 2 L
• 4 L

Why choose the Reef Fusion 2 from ReefSolution?

For complete, high-volume dosing, combine Seachem Reef Fusion 2 4L with Seachem Reef Fusion 1 4L in a 1:1 ratio. Automate your routine with the Kamoer X1 Pro Dosing Pump and monitor your parameters with the Salifert KH/Alk Test Kit or the Hanna Checker Alkalinity for stable alkalinity maintenance.

Frequently Asked Questions

Is the 4L format the most economical for large reef aquariums?

Yes. The 4L format offers the best quantity-price ratio in the Reef Fusion range, ideal for systems of more than 200 gallons or SPS tanks with high alkalinity consumption and automated daily dosing.

Can Reef Fusion 2 be used alone to correct alkalinity?

Yes. Seachem confirms that the Reef Fusion 2 can be used individually to adjust alkalinity if your system has an imbalance between calcium and alkalinity.

What is the difference between Reef Fusion 2 and Reef Carbonate?

Reef Fusion 2 is designed as a 2-part system with Fusion 1 in a 1:1 ratio, concentrated at 4400 meq/L. Reef Carbonate is a standalone supplement at 4000 meq/L with a pK of 9.0 that stabilizes the pH at 8.3–8.4.