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PAR Requirements for SPS vs LPS vs Soft Corals
🪸 Different corals need different light intensity — This guide details exact PAR ranges for SPS, LPS, and soft corals, plus placement strategies for mixed reefs.
What PAR Do SPS Corals Need?
SPS (Small Polyp Stony) corals require 200‑350 PAR for optimal growth. Acropora species can tolerate up to 500 PAR with proper acclimation. Below 150 PAR, SPS lose color and growth slows.
SPS corals like Acropora, Montipora, and Pocillopora have high metabolic demands. They host dense zooxanthellae populations that need intense blue/violet light. Reefs.com research shows that Acropora grows 3x faster at 350 PAR than at 150 PAR. However, PAR above 450 can cause photoinhibition and bleaching unless acclimated over weeks. Place SPS on top of rockwork, directly under LED pucks or metal halide. Use a PAR meter to confirm levels. For a 24″ deep tank, you need high‑output LEDs (Radion, Kessil) or T5/LED hybrid to achieve 300+ PAR at the top.
🧬 SPS PAR guide
– Acropora: 250‑450 (optimal 350)
– Montipora: 200‑350
– Seriatopora (birdsnest): 200‑300
– Stylophora: 200‑350
– Pocillopora: 200‑350
– Montipora: 200‑350
– Seriatopora (birdsnest): 200‑300
– Stylophora: 200‑350
– Pocillopora: 200‑350
What PAR Do LPS Corals Need?
LPS (Large Polyp Stony) corals thrive in 75‑150 PAR. Euphyllia (torch, hammer) prefer 80‑120 PAR. Trachyphyllia (open brain) and Scolymia do best at 50‑100 PAR.
LPS corals have larger polyps and often feed on particles, so they require less light energy from zooxanthellae. Too much light (above 200 PAR) causes them to retract polyps, bleach, or even die. Advanced Aquarist notes that LPS placed under SPS lighting often suffer tissue recession. Place LPS on the sand bed or lower rockwork, in areas with moderate flow. If your tank has high PAR (300+ in upper zones), position LPS in shaded overhangs or at the tank edges. Start them at 50‑70 PAR and increase slowly if they expand fully.
🐚 EuphylliaTorch, Hammer, Frogspawn: 80‑120 PAR
🧠 TrachyphylliaOpen brain, Wellsophyllia: 50‑100 PAR
🟤 AcanthophylliaMeat coral: 50‑80 PAR
What PAR Do Soft Corals Need?
Soft corals (zoanthids, mushrooms, leathers) need 50‑100 PAR. Some zoanthids tolerate up to 150 PAR, but higher intensities cause fading. Mushrooms prefer low light (30‑60 PAR).
Soft corals lack a calcium carbonate skeleton and have less demanding photosynthetic needs. They often thrive in the lower half of a mixed reef. Too much light causes them to close up, lose color, or melt. NOAA indicates that many soft corals originate from turbid or deeper waters. Place them on sand or low rock. For zoanthids, you can gradually acclimate to 120‑150 PAR for brighter colors, but watch for curling. Mushrooms (Rhodactis, Discosoma) do best at 30‑60 PAR; under high light they shrink and may detach.
How to Place Corals in a Mixed Reef Based on PAR?
Map your tank’s PAR: top 1/3 for SPS (200‑350), middle 1/3 for LPS (100‑200), bottom 1/3 and sand for soft corals (50‑100). Adjust with shading or moving rockwork.
Use a PAR meter to create a grid. Then designate zones. For example, in a 24″ deep tank with Radion XR15 at 10″ height, the top 6″ may have 300‑400 PAR, middle 6‑12″ 150‑250 PAR, bottom 12‑18″ 80‑150 PAR. Place Acropora on top, Euphyllia on middle rock, zoas on lower rock, mushrooms on sand. BRS PAR maps show real examples. If you have a very intense light, create shaded areas using overhangs or place less demanding corals in corners. You can also use egg crate to diffuse light for lower sections. Always observe coral behavior: if polyps are retracted or color fades, move to different PAR zone.
📐 Placement cheat sheet: SPS → top 6″; LPS → middle 8‑12″; Soft → lower 12‑18″ and sand.
Can You Keep SPS and LPS Together in the Same Tank?
Yes, by creating vertical PAR zones and managing flow. Place SPS high, LPS mid to low. Also consider aggression – some LPS have sweeper tentacles that can sting SPS.
Many successful mixed reefs combine SPS, LPS, and soft corals. The key is to arrange rockwork to create a range of PAR levels. For example, build a tall rock structure with a flat top for SPS, and lower ledges for LPS. Keep 3‑4 inches between SPS and aggressive LPS (e.g., Galaxea, Euphyllia). Reef2Reef examples. Use a PAR meter to ensure each coral receives its target range. Also, note that LPS and soft corals release chemicals (allelopathy) that can inhibit SPS; run activated carbon and perform regular water changes.
⚔️ Aggressive LPS: Galaxea, Euphyllia (torch/hammer), and some favia have long sweeper tentacles that reach several inches. Keep them away from SPS.
What PAR Do NPS (Non‑Photosynthetic) Corals Need?
NPS corals (sun corals, dendronephthya) lack zooxanthellae and require very low PAR (5‑20) or total darkness. They depend entirely on direct feeding (phytoplankton, zooplankton).
These corals should be placed in caves or overhangs with almost no light. High PAR will cause them to close permanently and die. If you keep NPS, use a dedicated low‑light zone or feed them heavily without strong lighting. Reefs.com NPS guide. For most hobbyists, avoid mixing NPS with high‑light SPS because feeding schedules conflict.
🌑 NPS examples
Tubastrea (sun coral), Dendronephthya, Rhizotrochus. PAR < 20, often twilight zone.
How to Acclimate Corals to Higher PAR?
Start new corals at 50% of target PAR for 1‑2 weeks, then increase 10% weekly. Use light acclimation mode on LEDs or move corals upward gradually over 4‑6 weeks.
Sudden PAR increase causes bleaching. For example, if your tank’s top rock has 350 PAR and you buy an Acropora from a tank with 150 PAR, place it at the bottom (100 PAR) for 2 weeks. Then move it up 3 inches every week. BRS acclimation protocol. Most modern LEDs have an acclimation mode that gradually increases intensity over a set period (e.g., Radion’s “acclimation” setting). Watch for signs: if coral browns (too little PAR) or pales (too much), adjust. For LPS and soft, raising PAR too fast causes immediate polyp retraction.
💡 Easy method: Use window screen mesh. Place 2 layers over tank and remove one layer every 3 days over 2 weeks. This reduces PAR by about 50% initially.
How to Measure PAR in Your Reef Tank Without Expensive Meter?
Rent a PAR meter (Apogee MQ‑510) from local reef club or online (BRS rental). Phone apps are inaccurate. Borrow from fellow hobbyist – PAR meters are widely shared.
Buying a PAR meter costs $350‑500. Instead, check BRS rental program ($50‑70 for a week). Many local reef clubs have meters for members. If you cannot get a meter, use manufacturer PAR charts for your light and approximate based on mounting height. However, charts assume clear water and perfect optics – your real PAR may be 20‑30% lower. For critical SPS tanks, a meter is highly recommended. Once you have baseline readings for your light and rockwork, you can rely on that data for years.
📚 Explore more reef lighting guides:
← Main Lighting Guide (T1)
Reef Hub (T2)
You are here
Reef brand comparison
Coral acclimation guide
PUR vs PAR explained
Bleaching prevention
📊 Quick reference: PAR ranges by coral type
| Coral type | Ideal PAR | Placement in tank | Example species |
|---|---|---|---|
| SPS (Acropora) | 300‑450 | Top 6″, direct light | A. millepora, A. tenuis |
| SPS (Montipora) | 200‑350 | Upper 1/3 | M. capricornis, M. digitata |
| LPS (Euphyllia) | 80‑120 | Middle, moderate flow | Torch, Hammer, Frogspawn |
| LPS (Trachyphyllia) | 50‑100 | Sand bed, low flow | Open brain, Scolymia |
| Soft (Zoanthids) | 50‑120 | Lower rock, edges | Zoas, Palythoa |
| Soft (Mushrooms) | 30‑60 | Shaded, low rock | Discosoma, Rhodactis |
📖 References & further reading
• Reefs.com – Coral PAR requirements
• Advanced Aquarist – PUR vs PAR
• NOAA – Coral reef light
• BRS PAR maps for common fixtures
• BRS – Coral acclimation guide
• Reef2Reef – Mixed reef lighting examples
• Reefs.com – Coral PAR requirements
• Advanced Aquarist – PUR vs PAR
• NOAA – Coral reef light
• BRS PAR maps for common fixtures
• BRS – Coral acclimation guide
• Reef2Reef – Mixed reef lighting examples
