Reef Tank Basics

Jan 19, 2026

Reef Tank Basics: Building a Healthy Saltwater Reef

Starting your first reef tank is one of the most rewarding steps in the saltwater aquarium hobby. Corals, invertebrates, and reef-safe fish can create a living slice of the ocean in your home—but only if you get the fundamentals right. This guide covers the core reef tank basics so you can avoid common mistakes and build a stable, thriving system.

Planning Your First Reef Tank

Before buying equipment or livestock, take time to plan your system. Good planning saves money, prevents frustration, and keeps your animals healthier.

Choosing the Right Tank Size

For most beginners, a reef tank in the 40–75 gallon range is ideal. Smaller tanks are cheaper, but water parameters swing faster, making them less forgiving. Larger tanks are more stable but cost more to set up and maintain.

Nano reefs (under 30 gallons): Beautiful, but best for hobbyists who already understand water chemistry.
Mid-size reefs (40–75 gallons): Great balance of stability, cost, and livestock options.
Large reefs (90+ gallons): Excellent stability and stocking flexibility, but higher upfront and ongoing costs.

As you plan, think about future upgrades. If you know you’ll eventually want more demanding corals, it’s worth reading our guide to choosing reef tank equipment so you can buy once instead of upgrading multiple times.

Essential Equipment for a Basic Reef

You don’t need every gadget on the market, but a few core pieces of equipment make reefing far easier:

Quality protein skimmer: Helps remove dissolved organics and keeps nutrients in check.
Reliable heater and thermometer: Aim for 77–79°F (25–26°C) and avoid big temperature swings.
Reef-capable lighting: LED fixtures designed for coral growth are the most popular choice today.
Powerheads or wavemakers: Provide strong, random flow so corals can breathe and shed waste.
RO/DI water source: Using purified water dramatically improves stability and algae control.

For a deeper breakdown of these items and how they work together, check out our saltwater aquarium setup checklist.

Water Parameters and Reef Maintenance

Reef tanks succeed or fail on water quality. Stability is more important than perfection, but you’ll want to stay within proven ranges.

Key Reef Tank Parameters

Salinity: 1.025–1.026 specific gravity (use a calibrated refractometer).
Temperature: 77–79°F (25–26°C).
pH: 8.0–8.4.
Alkalinity: 8–10 dKH.
Calcium: 400–450 ppm.
Magnesium: 1250–1350 ppm.
Nitrate: 2–20 ppm (low, but not zero).
Phosphate: 0.02–0.10 ppm.

Tip: Test weekly in the beginning and log your results. Trends matter more than any single reading.

Simple Maintenance Routine

A consistent routine is the easiest way to keep your reef happy:

Daily: Check temperature, equipment, and livestock behavior. Top off evaporated water with RO/DI.
Weekly: Perform a 10–15% water change, clean glass, and test core parameters.
Monthly: Clean pumps and skimmer, replace or rinse mechanical filtration, and inspect cables and plugs.

As your corals grow, you may need to dose calcium, alkalinity, and magnesium. When that time comes, our beginner reef corals guide can help you match your dosing strategy to the types of corals you keep.

Stocking Your Reef Tank Wisely

Livestock choices can make or break a new reef. Add animals slowly and research each species in advance.

Start with hardy, peaceful fish such as clownfish, gobies, and some wrasses.
Introduce a cleanup crew (snails, hermit crabs, and other inverts) once the tank has completed its nitrogen cycle.
Begin with forgiving corals like soft corals and some LPS (e.g., zoanthids, mushrooms, and hammer corals).

Add only one or two fish at a time, testing water after each addition. If nutrients spike, slow down and let the system catch up.

Wrapping Up: Focus on Stability and Patience

The core of reef tank basics comes down to three things: planning, stability, and patience. Choose an appropriate tank size, invest in reliable life-support equipment, maintain stable water parameters, and stock slowly with compatible animals. If you focus on these fundamentals and resist the urge to rush, your reef tank can grow into a vibrant, long-lived ecosystem you’ll enjoy for years.