Reef DLI Calculator
Reef DLI calculator
What is DLI? Daily Light Integral is the total light your coral gets in one day (mol/m²/day) — peak PAR × how long the lights run, including short ramps. PAR is brightness at one moment; DLI is the full daily dose, which is what corals actually grow on.
Most reef LEDs only ramp for 10–60 minutes, then stay at peak PAR for the rest of the day. Enter your schedule below — short ramps barely change DLI vs flat peak.
Mode
1. Peak PAR
Measure underwater at the coral once lights are at full intensity — not during the ramp.
2. Your daily schedule
Ramp up → hours at peak → ramp down. Typical: 0.2–1.0 h ramps (about 10–60 minutes), then most of the day at peak.
Often 0.2–1.0
Full intensity time
Often 0.2–1.0
Total lights-on: 9.0 h · Effective peak-hours for DLI: 8.5 h