Red Sea Reef Care 4 Part RCP Small 160ltr

• Manual or automated dosing – works by hand or through a Red Sea ReefDose.
• Sized for reefs to 160 L – including nano and small reef tanks, built around roughly three months of daily dosing.
• Four parts, one ratio – Part 1 (Calcium & Magnesium+), Part 2 (Alkalinity/KH & pH stabiliser), Part 3 (Iodine & Potassium) and Part 4 (Iron & Bioactive Elements), bottled so all four run out together.
• 36 major, minor and trace elements in the ratio found in coral skeleton and tissue.
• Set your dose from testing, using a Red Sea Reef Foundation test kit, rather than the label rate alone.

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.

For a 160 L reef dosed at the mixed-reef guide rate (~3 mL per 100 L per day), that's under 5 mL of each part daily – at the gentler ultra-low-nutrient rate, a nano reef well under 160 L will stretch the Small pack out past three months.

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.

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.

Included: four dosing solutions – Calcium & Magnesium+, Alkalinity/KH & pH Stabiliser, Iodine & Potassium, and Iron & Bioactive Elements – proportioned for a 160 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 nano and small saltwater reef tanks from about 40–160 L running coral, where calcium, alkalinity and magnesium need topping up against 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.

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; no special handling required for this pack size.

Is this suitable for a nano reef under 100 L?

Yes – the Small pack is sized for reefs up to 160 L, so a 40–100 L nano reef will get more than three months from it, particularly at the lower ultra-low-nutrient dose rate.

Why buy the Small pack instead of splitting a Medium pack with another tank?

The four bottles in every RCP pack are proportioned to finish together at that pack's rated volume – splitting a Medium pack across two smaller tanks works arithmetically, but you'd need to divide each of the four bottles accurately rather than dosing straight from the bottle.

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.