• Liquid remineraliser - dose directly into water, no mixing required
• Restores calcium, magnesium, potassium and sodium to physiologically balanced levels
• 5 mL raises GH by 1 meq/L (2.8 dGH) in 40 L of water
• Prevents osmotic stress and shock caused by mineral-stripped water
• Four pack sizes - 100 mL, 250 mL, 500 mL and 4 L - for nano tanks through to multi-tank systems

For occasional top-ups on a single small tank, the 100 mL or 250 mL bottle covers plenty of water changes before it runs out. Owners doing regular weekly water changes on a larger tank get better value from the 500 mL size, which works out cheaper per litre treated (see the cost-per-litre table below). The 4 L pack is a big step up in both price and volume of water it can remineralise, so it suits multi-tank homes, breeders or shops running RO/DI systems continuously rather than a single average display tank.

Suitable for restoring GH in RO/DI, distilled, or soft/rain water used for freshwater community aquarium top-ups and water changes.

Not suitable for planted aquariums - Replenish's mineral salts include sodium and chloride, which can be detrimental to live plants; Seachem's own recommendation for planted setups is Equilibrium instead. Replenish's ingredient list is limited to mineral salts, so it does not condition tap water - pair it with a dechlorinator/conditioner when treating chlorinated or chloraminated tap water rather than using it as a stand-alone conditioner.

Add 5 mL (one capful) of Replenish per 40 L of RO/DI, distilled or soft/rain water to raise GH by 1 meq/L (2.8 dGH). For the recommended restoration level of 1-2 meq/L (2.8-5.6 dGH) typical of a freshwater community tank, dose 5 mL per 20-40 L of source water, adjusting within that range to suit the GH your fish need.

Using Seachem's conservative dose of 5 mL per 20 L (the higher end of the recommended restoration range), here is how far each size stretches and what that works out to per litre of water remineralised.

Pair Replenish with a reverse osmosis/DI unit for producing purified source water, and a GH or mineral test kit so you can confirm hardness before and after dosing.

Covered by Australian Consumer Law consumer guarantees. Contact us for delivery timeframes to your address; faulty or incorrectly supplied items are eligible for return or replacement in line with ACL.

Is Replenish safe for marine tanks?

Replenish is formulated and documented by Seachem for freshwater use. It is not marketed as a marine or reef remineraliser, so for saltwater systems use a dedicated marine salt mix or reef mineral supplement instead.

How is Replenish different from a water conditioner?

Replenish only restores minerals (GH) to demineralised water. It does not contain dechlorinators, so it is not a substitute for a conditioner such as one that neutralises chlorine, chloramine or ammonia in tap water.

Which size lasts longest for a weekly water-change routine?

The 500 mL bottle offers a good balance of value and shelf life for a typical weekly water-change routine, while the 4 L pack suits larger volumes or multiple tanks (see the size guide and cost-per-litre table above).

Can I dose it directly into a tank with fish in it?

Replenish is added directly to water with no mixing step, but as with any mineral or GH adjustment, dose gradually and avoid large, sudden swings in hardness in a tank that already has fish in it.

What GH increase does one dose give?

5 mL of Replenish raises GH by 1 meq/L (2.8 dGH) in 40 L of water; the recommended restoration range for RO/DI water is 1-2 meq/L (2.8-5.6 dGH).

Does Replenish work in planted tanks?

No - because it contains sodium and chloride, Seachem recommends Equilibrium rather than Replenish for planted aquariums.