Full-spectrum LED (default)
White + warm + cool LEDs covering 6500K spectrum. Universal: works for fish-only, low-tech planted, community tanks. Fluval Aquasky, NICREW Classic, Eheim ClassicLED. Plug-and-play, dimmable on most models.
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Aquarium Lighting
💡 Aquarium lighting
Aquarium lighting — light the tank, not the algae
Get aquarium light wrong and you get green water + black-beard algae within weeks. Get it right and a planted tank looks like a window into another world. Most tanks are running too long, too bright, with the wrong spectrum. Here's the simple ruleset for clear, healthy water.
Photo: Aleksey Bystrov / Pexels
What we'll be stocking
Light types
Plant-spec LED (high-PAR)
Higher PAR (photosynthetically active radiation) for live plants. Required for carpet plants, stem plants, demanding species. Twinstar, Chihiros, Fluval Plant 3.0. Match light output to plant difficulty: low-tech 30 PAR, high-tech 80+ PAR.
Low-light LED
For Anubias, Java fern, mosses, low-tech planted tanks. Standard hood-light is enough. Save the high-PAR units for demanding plants — too much light + no CO₂ = algae bloom.
Reef / marine LED
Higher blue spectrum (12,000–20,000K) for coral fluorescence + zooxanthellae photosynthesis. AI Hydra, Kessil, EcoTech Radion. Marine-only — overkill (and wrong spectrum) for freshwater.
Smart / app-controlled
Wifi/app dimmable units (Fluval Aquasky, Chihiros) — set sunrise/sunset curves, weather effects, schedule. Adds €30–€60 over basic LED but pays back via algae prevention + plant growth. Set + forget, mostly.
Get the photoperiod + spectrum right
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6–8 hours per day, hard cap
A wild river gets ~6 hours of useful light per day (filtered by water depth + clouds). Aquariums running 10–12 hours = algae heaven. Use a plug timer (€8) or smart light. 6h for low-tech, 8h for high-tech CO₂ planted. Never "all day".
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Spectrum (Kelvin) matters
6,500K = daylight, ideal for plants + colour rendering. 8,000K+ = colder, more blue, encourages algae in some tanks. Below 5,000K = warm/yellow, fades fish colours, doesn't support plants. Stick close to 6,500K for freshwater.
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Match wattage to tank size
Old "watts per gallon" rule is dead with LEDs. Modern guide: 0.25–0.5 W LED per litre for low-tech, 0.5–1 W LED per litre for planted, 1+ W LED for high-tech CO₂. PAR meters are the precise way; for most home tanks the manufacturer chart is fine.
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Algae siesta trick
For algae-prone tanks: 4 hours light, 4 hours dark, 4 hours light, then dark for the rest of the day. Plants tolerate it; algae need continuous light to bloom. Cheap fix that helps with persistent green-water tanks.
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Position away from window
Sun on the tank = uncontrolled extra light + heat. Algae bloom guaranteed within 2 weeks. Position aquarium 2 m+ from a sunny window, blackout-curtain side if unavoidable. Cool side of the room with stable 22–25 °C ideal.
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Replace bulbs / units when output drops
LEDs lose 20–30% intensity over 3–4 years. If your plants suddenly stop growing or algae creeps back, light fade is often the cause. Most LEDs are not user-replaceable bulbs — replace the whole unit. Old fluorescent T5 tubes lose half their output in 6 months.
🛒 We don't stock this directly
Alleavia doesn't stock or ship pet supplies. Our breed-matched buying guides pick the right aquarium lighting gear and link out to Amazon — and the calculators, breed guides and AI vet tools below are always free.
Frequently asked questions
How long should the aquarium light be on?
6–8 hours per day, with a plug timer or smart-LED schedule. Longer = algae bloom, especially in tanks with sun exposure or high nutrient load. The siesta method (4h on / 4h off / 4h on) helps stubborn algae cases.
Why is my tank getting green water / black algae?
Three usual suspects: (1) too long photoperiod (>8 hours), (2) ambient sunlight on the tank, (3) excess nutrients (overfeeding, no plants, dirty filter). Reduce light to 6 hours, move tank from sun, do a 30% water change, clean the filter. Persistent issues = test water for nitrate.
Do I need a special light for live plants?
Anubias, Java fern, mosses, hornwort, vallisneria — basic LED hood-light works. Carpet plants, demanding stem plants (HC, glosso, rotala), most red plants — need higher-PAR plant-spec LEDs. Start low-tech with hardy plants; upgrade lights after you've mastered the easy ones.
Are smart wifi-controlled lights worth it?
For most planted tanks, yes. €30–€60 over basic, gives sunrise/sunset curves (less stress on fish), automatic schedule, dimming for algae control. Set-and-forget for years. Skip it if your tank is fish-only with no plants — basic LED + a €8 plug timer is enough.