Choose your route
Commercial comparison
The best reef aquarium lights in the UK
Five current LED routes compared by claimed spread, power, control, mounting and checked UK price.
Sizing method
Match a reef light to tank dimensions
A repeatable way to turn tank length, width and water depth into a sensible fixture shortlist.
Nano decision
The best nano reef lights for your tank size
Shortlists for 40–45cm cubes, 50cm footprints and 60cm-wide compact systems.
Interactive calculator
Reef light coverage calculator
Estimate a conservative source count from coral-zone dimensions, depth, livestock plan and aquascape.
Head-to-head
AI Prime 16HD vs Radion XR15 G6 Pro
Compact value versus premium distribution headroom, with installed and running-cost context.
Head-to-head
AI Prime 16HD vs Kessil A360XE
Compare point-source shimmer, built-in control, published fields and complete ownership cost.
Head-to-head
AI Prime 16HD vs ReefLED G2 60
Two similarly powered compact routes compared by geometry, ecosystem fit and mounting friction.
Tank-width guide
Best reef light for a 60cm tank
Single broad source or two compact lights: build the shortlist around the actual coral zone.
Tank-width guide
Best reef light for a 90cm tank
Plan overlap, fixture count and front-to-back coverage for a three-foot reef.
Tank-width guide
Best reef light for a 120cm tank
Design a serviceable multi-light array for a four-foot mixed or SPS-led reef.
Measurement guide
Reef light PAR explained
Understand what a PAR map proves, what it misses and how to use it safely.
Installation guide
Reef light mounting height
Balance spread, intensity, glare, blending and maintenance access.
Ownership cost
Reef lighting electricity cost UK
Calculate label ceilings, programmed duty and measured annual lighting cost.
THE LIGHTING RULE
Coverage is a rectangle, not a litre rating.
Two tanks can hold the same litres but need different lighting because their length, front-to-back width and water depth differ. Begin with the illuminated footprint, then account for coral placement, shadowing, mounting and the number of fixtures.