Red Sea Reef Care 4 Part RCP Large 600ltr
Cost per litre
$0.50
Suits tanks
Up to 600 L
Water type
Saltwater (Reef)
Red Sea Reef Care 4 Part RCP Large 600ltr
One coordinated dosing program covers calcium, alkalinity, magnesium and all the trace elements a 600 L reef consumes. The Red Sea 4-Part RCP (Reef Care Program) — Large pack — supplies four proportioned bottles sized to run a mixed reef up to 600 L for roughly three months, so major and trace elements are replenished in the same balance corals draw them from the water.
Key features
- Four parts, one ratio — Part 1 (Calcium & Magnesium+), Part 2 (Alkalinity/KH & pH stabiliser), Part 3 (Iodine & Potassium) and Part 4 (Iron & Bioactive Elements) are bottled in the proportions a reef actually consumes them, so all four bottles run out together instead of one running dry early.
- Sized for reefs to 600 L — the Large pack is built around roughly three months of daily dosing for a mixed reef at that volume; smaller or larger reefs use the dose rate below to work out their own duration.
- Covers 36 major, minor and trace elements across the four parts, matched to the ratio found in coral skeleton and tissue.
- Works with manual dosing or a Red Sea ReefDose for automated, split dosing through the day.
- Pairs with Red Sea's Reef Foundation and Coral Colours test kits so dosing is set from your own measured uptake, not a generic label rate.
Specifications
| Spec | Detail |
|---|---|
| SKU | RED878 |
| Barcode | 7290116399034 |
| Reef volume | Up to 600 L |
| Approx. duration | ~3 months, mixed reef, dosed to programme |
| Parts included | 4 — Ca/Mg, Alkalinity, Iodine/Potassium, Iron/Bioactive Elements |
| Water type | Saltwater (reef) |
| Dosing method | Manual or Red Sea ReefDose 4 |
Which size do I need?
All three RCP packs dose the same four elements in the same ratio — they differ only in reef volume and cost per 100 L over the roughly three-month cycle.
| Pack | Reef volume | Approx. cost per 100 L, per 3-month cycle |
|---|---|---|
| Small | Up to 160 L | $68.13 |
| Medium | Up to 300 L | $63.00 |
| Large | Up to 600 L | $49.83 |
At 600 L the Large pack is the best value per 100 L of the three sizes — worth buying up a size even if your reef is a little under 600 L, provided you'll use it within the ~3-month window.
Dosing and elemental targets
Foundation elements (Parts 1 and 2) are formulated so 1 mL per 100 L raises calcium by 2 ppm, magnesium by roughly 1 ppm, and alkalinity by about 0.034 dKH — but the right daily dose is whatever your reef is actually consuming, not the label maximum.
| Reef type | Typical daily dose |
|---|---|
| Mixed reef | ~3 mL per 100 L, each part |
| SPS-dominant | ~4 mL per 100 L, each part |
| SPS frag / high growth | ~6 mL per 100 L, each part |
| Ultra-low-nutrient system | ~2 mL per 100 L, each part |
Never exceed a daily increase of 20 ppm calcium, 0.5 meq/L (1.4 dKH) alkalinity or 10 ppm magnesium — spread any larger correction over several days. When dosing manually, add magnesium first, then alkalinity, then calcium, with about 10 minutes between each. Part 4 (Iron & Bioactive Elements) has no single target ppm — Red Sea's guidance is to dose it in proportion to how much of Parts 1–3 your reef is using.
What's included / Not included
Included: four dosing solutions — Calcium & Magnesium+, Alkalinity/KH & pH Stabiliser, Iodine & Potassium, and Iron & Bioactive Elements — proportioned for a 600 L reef over roughly three months.
Not included: dosing pump, test kits, and the calcium/alkalinity/magnesium test results you'll need to set your own daily dose accurately. A Red Sea Reef Foundation test kit and either manual dosing or a ReefDose unit are what you'll still need to run the programme properly.
Suitable for, and not suitable for
Suitable for established saltwater reef aquariums running coral, where calcium, alkalinity and magnesium need topping up against coral consumption.
Not suitable for fish-only or newly cycled tanks with no coral demand — dosing without a measurable uptake risks pushing parameters too high. Not a substitute for water changes, and not intended for freshwater systems.
Warranty and delivery
Covered by the standard manufacturer guarantee against faulty product, in addition to your rights under Australian Consumer Law. Liquid reef additives ship as standard parcel freight from Brisbane; no special handling required for this pack size.
Common questions
Do I need a test kit to use this?
You can dose to the tank-type guide above as a starting point, but Red Sea's own instructions recommend testing calcium, alkalinity and magnesium regularly and adjusting the dose to what your reef is actually using — dosing blind risks over- or under-shooting.
What's the difference between the Small, Medium and Large packs?
The same four elements in the same ratio — only the bottle sizes and the reef volume they're built for change. See the size comparison table above.
Can I dose all four parts at once?
Red Sea recommends spacing magnesium, alkalinity and calcium about 10 minutes apart when dosing manually, to avoid a local spike that can precipitate elements out of solution. The trace element part (Part 4) isn't time-sensitive in the same way.
Will this suit an SPS-dominant tank?
Yes — SPS-dominant and frag systems typically consume more of each element, so they'll use the programme faster than the ~3-month mixed-reef estimate. Use the SPS dose rates above and expect to reorder sooner.
Does this replace regular water changes?
No. Dosing replaces what corals consume between water changes; it doesn't address the build-up of dissolved organics that water changes handle.
