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Lighting Calculator
Find the right amount of light for your planted tank. Gives a lumens and wattage range based on tank volume and your plant goals.
Most stem plants, swords and carpeting with CO₂. The sweet spot for planted tanks.
Recommended Light
Light Output
2000 – 4000 lm
lumens for the tank
LED Fixture
20 – 40 W
≈100 lm/W
T5 / CFL
33 – 67 W
≈60 lm/W
Watts per Litre
0.020 – 0.040 W/L
rule-of-thumb
Wattage is a rough guide — modern LEDs are far more efficient. Height matters too: light on a 60 cm-deep tank needs ~2× the lumens to reach the substrate compared to a 30 cm tank.
Related Reading
Guides that cover this topic in depth