Aqua Medic Reef Life Hydrocarbonate 3-5mm 1ltr
Feeds calcium and alkalinity back into a reef tank as CO2 slowly dissolves it. Aqua Medic Reef Life Hydrocarbonate is a pure calcium carbonate media in a 3–5 mm (medium) grain, sized for use in a CO2-fed calcium reactor. As CO2 passes through the reactor chamber it lowers the pH inside, and the acidified water dissolves the media into calcium bicarbonate — which is what actually replaces the calcium and carbonate hardness a reef consumes.
Key features
- Pure calcium carbonate — no binders or fillers, so what dissolves is what's stated: calcium, carbon and oxygen.
- 3–5 mm medium grain — a middle ground between fine grades (faster dissolving, more prone to channelling and compaction) and coarse grades (slower, longer bed life). Matches the media size most calcium reactor manufacturers specify as their default fill.
- Restores calcium and alkalinity together — a calcium reactor addresses both parameters from one media, rather than dosing them separately.
- Also usable outside a calcium reactor — as a calcite (KH-buffering) filter media, or as a substrate component in marine and African cichlid tanks, where its buffering effect on pH is useful rather than incidental.
Specifications
| Composition | Pure calcium carbonate |
|---|---|
| Grain size | 3–5 mm (medium) |
| Pack size | 1 L |
| Primary use | CO2-fed calcium reactor media |
| Other uses | Calcite filter media; substrate additive for marine and African cichlid tanks |
| Water type | Marine / reef |
Dosage and directions
Fill the calcium reactor chamber with media per the reactor manufacturer's instructions, then run CO2 into the chamber to bring the internal pH down until the media begins dissolving. Effluent pH and drip rate are adjusted to match the tank's calcium and alkalinity consumption, not to a fixed schedule — a higher bioload or faster coral growth draws the media down faster.
How long does a litre last?
Aqua Medic does not publish a fixed "treats X litres" figure for this media, and that's genuinely because there isn't one: consumption is driven by your tank's calcium and alkalinity demand and your reactor's effluent rate, not by a dose ratio to system volume the way a salt mix or liquid additive is. As a rough planning guide, a lightly stocked reef draws down a reactor chamber far more slowly than an SPS-heavy, fast-growing system — track your Ca and KH test results rather than the calendar.
Suitable for, and not suitable for
- Suitable for: any CO2-fed calcium reactor sized to take loose media in this grain range; marine and reef systems needing ongoing calcium and alkalinity replacement.
- Not suitable for: freshwater planted tanks wanting to avoid raised hardness — this media will buffer pH upward and add hardness, which is the opposite of what most planted setups want.
Care and maintenance
Top up or replace media once the bed visibly reduces in volume or Ca/KH readings drift down despite normal reactor operation. Rinse new media isn't required before use.
Warranty and delivery
Sold as a consumable reactor media; standard freight, no special handling required.
Common questions
Does this replace dosing calcium and alkalinity separately?
In a working calcium reactor, yes — the dissolving media supplies both, which is the main reason reactors are used over two-part or all-in-one liquid dosing on larger or heavily stocked systems.
Can I use the fine or coarse grade instead?
This is the 3–5 mm medium grade. Aqua Medic also sells fine and coarse grades separately — finer grades dissolve faster but compact more readily, coarser grades last longer between top-ups but dissolve more slowly.
Will it affect my tank's pH outside the reactor?
Only via the effluent it produces, which is intentionally lower in pH inside the reactor and raises the tank's alkalinity and calcium once mixed in — it does not lower display tank pH when the reactor is running correctly.
