Red Sea 4-Part RCP Complete Reef Care Dosing System - Small (150L - 40 Gal)

The Red Sea 4-Part Reef Care Program Complete Dosing System — Small is a complete chemistry package for reef aquariums up to 150 L (40 US gallons). Perfect for nano and small reef tanks, this all-in-one system supplies the Calcium, Alkalinity, Magnesium, and Trace Colors supplements your corals need for growth and coloration, all from a single trusted source.

To dose accurately, we strongly recommend testing weekly with the Reef Foundation Pro Multi Test Kit (Ca/Alk/Mg), the Calcium Pro Test Kit, and the Trace Colors PRO Multi Test Kit.

Have a larger system? See the Medium (80 gal) or Large (160 gal) versions.

Browse more supplements and dosing products in our Maintenance & Water Care collection.

• Foundation A (Calcium+) — maintains calcium & strontium levels
• Foundation B (Alkalinity) — maintains dKH and carbonate buffer
• Foundation C (Magnesium) — maintains stable Mg
• Trace Colors A, B, C, D — trace elements for coral coloration

• Complete chemistry program in one package — no guesswork
• Sized for aquariums up to 150 L / 40 US gallons — ideal for nano and small reef tanks
• Balanced formulations prevent drift and keep parameters stable
• Designed to be used with Red Sea test kits for precise dosing
• Excellent value vs. buying each component individually

Do I have to use all four parts?
For the best coral response, yes. Each part targets a specific set of parameters and they're formulated to work together.

How do I know how much to dose?
Red Sea's dosing tables are based on test results. Test weekly with Red Sea test kits and adjust according to the included instructions.

Which test kits do I need?
At minimum the Reef Foundation Pro (Ca/Alk/Mg). For full program optimization, add the Trace Colors PRO kit.

Is this the right size for my tank?
The Small kit is ideal for aquariums up to 40 US gallons — perfect for nano reefs. For larger reefs, use the Medium or Large versions.