Nano Reef Lighting PAR Requirements: AI Prime, Kessil A80, Radion
Nano reef tanks live or die by light intensity, and the difference between a thriving SPS garden and a tank of browned-out frags almost always comes down to PAR delivered at coral depth rather than wattage on the label. This guide to nano reef lighting PAR requirements compares the three fixtures most Singapore nano reefers end up cross-shopping — the AI Prime 16HD, the Kessil A80, and the Ecotech Radion XR15 G6 — with on-tank PAR numbers measured at different depths and placement zones. The figures below come from PAR meter logs at Gensou Aquascaping at 5 Everton Park across multiple customer tanks and our own display systems.
Quick Facts
- Softies: 50-150 PAR, any placement, forgive most fixtures
- LPS: 100-250 PAR, mid-tank placement, moderate flow
- SPS: 250-400 PAR, upper third, strong flow
- AI Prime 16HD: 55W, 300-380 PAR at 15 cm directly under
- Kessil A80: 15W, 150-220 PAR at 15 cm, narrow spread
- Radion XR15 G6: 95W, 400+ PAR at 15 cm, wide spread
- Always measure with a borrowed Apogee MQ-510 before stocking
Understanding PAR, PUR, and Mounting Height
PAR (Photosynthetically Active Radiation) measures photon flux across 400-700 nm — the usable spectrum for zooxanthellae. PUR (Photosynthetically Usable Radiation) narrows this to the wavelengths corals actually use efficiently. Manufacturers quote PAR; corals respond to PUR. Mounting height dramatically alters both — an AI Prime 16HD delivering 380 PAR at 15 cm drops to 210 PAR at 30 cm and 120 PAR at 45 cm. Most nano fixtures should mount 15-20 cm above the water surface for a 30-40 cm deep tank.
A PAR meter rental from local reef shops costs around $20-30 per day, and the reading settles arguments that online reviews cannot. Borrow before ramping corals.
AI Prime 16HD: The Nano Workhorse
At 55W, the Prime 16HD covers roughly a 40×40 cm footprint and delivers 300-380 PAR at 15 cm directly beneath the fixture at 100% intensity. At tank mid-depth (around 25 cm down) PAR drops to 200-260, and at sand level in a 35 cm deep tank it reads 150-190. This profile fits most all-in-one nano tanks in the 15-40 litre range.
Spread weakens at the corners — expect a 30-40% drop at the front-left and front-right corners compared to centre. SPS placement should stay central or mounted at the upper third. Soft corals tolerate corners without issue. In Singapore ambient with AC off, the Prime runs notably warm — ensure 10-15 cm air gap above the fixture or its thermal throttling kicks in.
Kessil A80 Tuna Blue: Small Tank Specialist
The A80 is a 15W pendant with a famously tight, shimmery beam. At 15 cm distance and 100% intensity, it delivers 150-220 PAR in a roughly 25 cm diameter pool. Outside that pool, PAR falls sharply — 80-100 at the edge, under 50 at the corners of a 30×30 cm tank. This makes the A80 ideal for a 10-15 litre pico or a 20 litre nano stocked primarily with soft corals and the occasional LPS placed directly under the beam.
For mixed or SPS-heavy nano tanks above 30 litres, a single A80 undershoots. Two A80s on a spreader bar solve the coverage problem but at a price point that approaches a single Prime. Choose the A80 for shimmer aesthetic or for a dedicated soft/LPS nano.
Radion XR15 G6: Overkill That Pays Off
The XR15 G6 pulls up to 95W and covers a 50×50 cm footprint comfortably. At 15 cm distance and 100% intensity, PAR readings of 400-450 are normal directly beneath, with 280-340 at 25 cm depth and 200-260 at sand level in a 40 cm deep tank. For SPS-dominant nano tanks in the 40-75 litre range, the G6 is the cleanest fit — it has the headroom to drive Acropora and Montipora without running at 100%, which extends LED life and reduces heat output.
Crowding a small cube tank with a 95W light creates thermal load concerns. Pair with a chiller or a well-sized chiller/fan combination, and set the fixture no lower than 15 cm above water to preserve even spread. The included mount has limited range — plan cabinet clearance during purchase.
Matching Coral Needs to PAR Zones
Design the tank as three vertical zones. Upper third (0-12 cm from surface): 250-400 PAR zone for SPS — Acropora, Stylophora, Montipora capricornis. Middle third (12-25 cm): 120-250 PAR zone for LPS, torch, euphyllia, zoanthids. Lower third (25 cm+): 50-120 PAR zone for mushrooms, ricordea, leathers. Photograph each frag’s original placement depth at the wholesaler and aim to match.
Acclimate new corals by starting at a low-PAR zone and moving up over 2-3 weeks, regardless of the fixture brand. A frag from a dim holding tank cooked under a Radion will bleach within a week.
Photoperiod and Ramp Schedule
Eight-hour full intensity with a 30-minute sunrise and 60-minute sunset ramp is standard. Run the peak period from 12:00 to 20:00 for evening viewing. Keep actinic hours flanking the peak — 30 minutes actinic-only ramp each side — for fluorescence viewing without driving algae. In Singapore ambient, photoperiods longer than 10 hours often trigger dinoflagellate or nuisance algae blooms in young tanks.
Measuring, Logging, and Long-Term Drift
Record a baseline PAR reading at 3-4 coral placement points when the fixture is new. Re-measure every 6 months. Output drops 10-15% by 20,000 hours and 25-30% by 40,000 hours. When baseline PAR drops 15% at a given placement, raise intensity 5-10% in firmware to compensate. Eventually, replace the fixture — running a failing LED at 100% to maintain PAR shortens remaining life and shifts spectrum unpredictably.
Where Singapore Buyers Overspend
The common mistake is picking the most expensive fixture for a 20 litre tank. A Radion on a 20 litre cube wastes most of its output and generates heat that a small chiller struggles to manage. Match fixture to tank depth and coral stocking rather than budget. A well-placed AI Prime at $550-600 beats a poorly positioned Radion at $1,100 in a small cube — our most-watched customer tanks consistently prove the point.
Related Reading
emilynakatani
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