- Sku: 1475
- Vendor: Seachem
Seachem Replenish
Seachem Replenish is a liquid blend of salts that restores the mineral content stripped out by reverse osmosis (RO) or deionizing (DI) filtration. It rebuilds General Hardness (GH) with a balanced mix of "soft" minerals (sodium, potassium) and "hard" minerals (calcium, magnesium), so RO and naturally soft water is brought back to a healthy, fish-friendly mineral balance. Explore the rest of our Seachem lineup and additives and supplements.
Why Remineralize RO/DI Water
RO and DI units produce nearly pure water, which is perfect as a blank slate but lacks the dissolved minerals fish use for osmoregulation, nerve function, and slime-coat health. Dosing Replenish with each water change restores GH to a target range without spiking pH or KH, so you stay in full control of your parameters. It is ideal for soft-water community tanks, livebearer setups that prefer harder water, and any aquarium filled with RO or DI water.
Features
Choose Your Size
| Spec | 100 mL | 250 mL | 500 mL | 4 L |
|---|---|---|---|---|
| Capfuls (5 mL) | ~20 | ~50 | ~100 | ~800 |
| Treats (base dose) | Up to 200 gal | Up to 500 gal | Up to 1,000 gal | Up to 8,000 gal |
| Best For | Nano & small tanks | Standard tanks | Frequent RO users | Stores & fish rooms |
| Form | Liquid | Liquid | Liquid | Liquid (bulk) |
Treatment estimates assume one capful per 10 gallons for a single GH-point increase. Soft water needing a larger boost uses proportionally more.
How to Use
Use 1 capful (5 mL) for every 40 L (10 US gallons) to raise General Hardness by about 1 meq/L (roughly 2.8 dGH, or 50 mg/L as CaCO3). For RO or DI water, add Replenish to the new water before a water change and dose to your target GH. Use a GH test kit to dial in the exact amount for your fish. Replenish only affects GH, so pair it with a carbonate buffer if your tank also needs KH support.
Specifications
| Specification | Detail |
|---|---|
| Type | Liquid GH remineralizer |
| Adjusts | General Hardness (GH) |
| Key minerals | Sodium, potassium, calcium, magnesium |
| Base dose | 5 mL per 10 gallons raises GH ~2.8 dGH |
| Water type | Freshwater (RO, DI, soft water) |
| Sizes | 100 mL, 250 mL, 500 mL, 4 L |
| Brand | Seachem |
Pairs Well With
Build a complete RO/DI water-prep routine: condition tap or top-off water with Seachem Prime, keep waste in check with Seachem Pristine, and browse our full range of maintenance and water care.
FAQ
Does Replenish raise pH or KH?
No. It targets General Hardness only. If you also need carbonate hardness, add a separate KH buffer.
Is it just for RO water?
It is ideal for RO and DI water, but it also works to firm up naturally soft tap water for fish that prefer more minerals.
How do I know how much to add?
Test your GH, then dose toward your target. One capful per 10 gallons raises GH by about 2.8 dGH, so adjust from there.
Will it harm plants or shrimp?
No. Most community fish, plants, and shrimp do well with a stable, moderate GH. For heavily planted RO tanks, many keepers prefer a plant-focused remineralizer instead.
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Seachem Replenish
