LPS Placement and Flow: Getting It Right

Why Placement Makes or Breaks LPS

Perfect water parameters and great lighting can still mean miserable-looking LPS if they're in the wrong spot. Placement trips up a surprising number of reefers.

Light Zones in a Typical Tank

Upper third (high PAR, 150–300+): SPS territory. Most LPS will bleach up here
Middle third (moderate PAR, 75–150): The sweet spot for Euphyllia, Duncans, and many LPS
Lower third / sandbed (low PAR, 30–80): Perfect for brain corals, Blastomussa, acans, and Goniopora

Measure, don't guess. A PAR meter (even borrowed or rented) reveals exactly what's going on. Different areas at the same height can have wildly different PAR depending on light spread and rockwork shadows.

Flow: The Most Underrated Factor

General rules for LPS flow:

Indirect, not direct. LPS should sway gently, not get blasted flat
Random or oscillating flow is better than constant laminar flow
10–20x tank volume turnover for an LPS-dominant tank

Species-specific flow preferences:

Euphyllia: Moderate, indirect. They should billow
Acans: Low. Very low
Duncans: Low to moderate. Gentle sway
Brain corals: Low. They inflate best in calm water
Goniopora: Moderate but oscillating
Blastomussa: Low. Basically still water with just enough movement to prevent dead spots

Placement by Species

Euphyllia — Mid-tank on rock shelves. 75–150 PAR. Leave GENEROUS space for sweeper tentacles.

Acans — Lower rockwork or sandbed. 50–100 PAR. Flat surfaces where they can spread.

Duncans — Mid to lower rock. 50–100 PAR. Give room to branch outward.

Trachyphyllia — Sandbed. Always sandbed. 50–100 PAR. Space to inflate.

Lobophyllia — Sandbed or rock shelves. 50–120 PAR. Room to expand.

Goniopora — Sandbed or low rock. 80–150 PAR. Space for polyp extension.

Blastomussa — Lowest part of the tank. 30–80 PAR. Those dim spots nothing else wants.

Common Placement Mistakes

Putting everything at the top: Most LPS belong in the middle or lower zones
Ignoring nighttime aggression: Check with a red torch after lights out
Not accounting for growth: Plan for where a coral will be in a year
Placing corals in dead spots: Even low-flow corals need some water movement
Moving corals too often: Give a new placement at least 2 weeks before deciding it's wrong

When placing a new LPS, start slightly lower and in slightly less flow than seems necessary. It's easier to move up than to recover a stressed coral.