Water flow is often the most underappreciated factor in coral health. In the wild, corals experience complex, multi-directional currents that keep them clean, deliver food, and remove metabolic waste. Replicating this in a closed system requires some planning.
Why Flow Matters
- Delivers dissolved oxygen and nutrients to coral tissue
- Removes detritus and waste products that fuel algae growth
- Prevents temperature stratification in the water column
- Stimulates natural polyp behavior and feeding response
Types of Flow
Laminar flow — steady, directional water movement. Good for specific target areas but can cause tissue damage from constant pressure on one spot.
Turbulent/chaotic flow — random, pulsing, multi-directional movement. Best for most corals and the closest simulation of natural reef conditions.
Recommended Turnover
- Soft corals: 20–40x tank volume per hour
- LPS: 40–60x tank volume per hour
- SPS: 60–100x+ tank volume per hour
Powerhead Placement
Place powerheads on opposing sides to create colliding currents in the center of the tank. Angle them slightly upward and away from corals to prevent direct blast. Gyre pumps excel at creating natural, random flow patterns throughout the entire water column.
Signs of Inadequate Flow
Watch for detritus accumulation on the sand bed or rocks, closed polyps during light hours, rapid algae growth in dead spots, or unexplained tissue necrosis on coral bases.