• Concentrated blend of carbonates and bicarbonates that raises and buffers alkalinity without adding calcium directly
• Formulated to be dosed daily or every second day, alongside Reef Fusion 1, at separate points in the tank
• 500 mL treats roughly 12,500 L of tank water at the standard dose, working out to under 1c per litre of system water dosed
• Suited to reef aquariums running hard corals, soft corals, clams and other calcifying invertebrates

Suitable for established reef aquariums running a two-part or three-part dosing regimen where alkalinity needs topping up between water changes.

Not suitable for use without first testing tank alkalinity, since dosing without knowing your starting level can push it up too far, too fast. Not intended to be dosed alone on an ongoing basis; pair it with Reef Fusion 1 so calcium and carbonate hardness are raised together and stay in balance.

Standard dose

Shake well, then add 1 mL of Reef Fusion 2 per 25 L (6.5 US gallons) of tank water, once every 1-2 days, to a high-flow area of the sump or display.

Maximum dose

Do not exceed 4 mL per 25 L in a single day, and do not raise alkalinity by more than 1 meq/L in any 24 hour period.

Cost per litre

At the standard dose (1 mL per 25 L), a 500 mL bottle treats around 12,500 L of tank water, which works out to under 1c per litre of system water dosed.

Never combine Reef Fusion 1 and Reef Fusion 2 concentrate directly; mixing the two concentrates together will cause them to cloud and precipitate. Dose each product a few minutes apart, at different points in the tank.

Test alkalinity regularly and aim to hold it between 4-6 meq/L, adjusting dose size or frequency to match your corals' calcification demand rather than increasing the dose blindly.

Reef Fusion 2 is designed to be dosed alongside Seachem Reef Fusion 1 (500 mL), the calcium and trace-element half of the same two-part system, rather than used on its own long-term.

This product is covered by the standard consumer guarantees under Australian Consumer Law. It is in stock in Australia and ships from our North Lakes, QLD warehouse.

Can I use Reef Fusion 2 without Reef Fusion 1?

You can dose Reef Fusion 2 alone if only your alkalinity is low, but Seachem designs the two products to be used together so calcium and carbonate hardness rise in balance. Dosing one without the other for extended periods can pull the two parameters out of the ratio corals need.

Why does alkalinity need to be dosed carefully?

Raising it too far or too fast can stress corals and, in tanks running high calcium, cause calcium carbonate to precipitate out of solution. Seachem recommends not raising alkalinity by more than 1 meq/L in a 24 hour period, and testing before increasing the dose.

Will it cloud the water?

Dosed at the recommended rate into a high-flow area, Reef Fusion 2 disperses without clouding. Adding it directly on top of Reef Fusion 1 concentrate, or dosing well above the stated rate, can cause temporary cloudiness or precipitation.

Is it reef-safe for clams and inverts?

Yes. Reef Fusion 2 is formulated for reef aquariums housing corals, clams and other calcifying invertebrates, the animals that draw carbonate hardness down as they build skeleton and shell.

How long will a 500 mL bottle last?

For a 200 L system dosed at the standard rate (8 mL per dose, every 1-2 days), a 500 mL bottle will last roughly 2-4 months. Larger tanks or more frequent dosing will use it faster; test regularly and adjust accordingly.