How to Light Scheduling for Reef Keeping - Step by Step
Step-by-step guide to Light Scheduling for Reef Keeping. Includes time estimates, tips, and common mistakes to avoid.
A well-planned reef light schedule does more than make corals look colorful - it directly affects growth, polyp extension, algae pressure, and overall tank stability. This step-by-step guide shows you how to program LED and T5 lighting with practical PAR targets, photoperiod lengths, and acclimation strategies for a healthier reef.
Prerequisites
- -A programmable reef light fixture or controller, such as LED units with adjustable channels or a T5 timer setup
- -A PAR meter, either owned, rented, or borrowed from a local reef club or store
- -Basic knowledge of your coral types, including whether they are soft coral, LPS, SPS, or mixed reef species
- -Tank details including aquarium depth, rockwork height, mounting height of the fixture, and current photoperiod
- -Recent water parameter readings for alkalinity, calcium, magnesium, nitrate, phosphate, salinity, and temperature
- -A notepad, spreadsheet, or reef tracking app to record schedule changes and coral response
Start by deciding whether your system is primarily a soft coral tank, LPS reef, SPS-dominant setup, or mixed reef. Different coral groups thrive under different intensity ranges, so your light schedule should match your livestock rather than a generic preset. As a practical baseline, aim for roughly 50-100 PAR for many soft corals, 75-150 PAR for most LPS, and 200-350 PAR for many SPS in their final placement zones.
Tips
- +List each coral and its placement zone so you can match top, mid, and bottom PAR targets realistically
- +If you run a mixed reef, prioritize stable lighting for your most demanding corals and place lower-light species in shaded areas
Common Mistakes
- -Using an SPS-style schedule on a tank full of LPS and soft corals
- -Assuming every coral from the same category wants the exact same PAR
Pro Tips
- *For mixed reefs, place acans, blastos, and many fleshy LPS in 75-125 PAR zones, while reserving 200-300 PAR shelves for montipora and many acropora species.
- *If you run T5 and LED together, let T5s cover the main 4-6 hour peak and use LEDs for ramp up, ramp down, and blue viewing periods.
- *Replace T5 bulbs on a consistent schedule, usually around 9-12 months for most reef systems, because spectrum and output shift gradually even if the bulbs still turn on.
- *Mounting reef LEDs a few inches higher often improves spread and reduces hotspot bleaching, even if you need a modest intensity increase to maintain the same PAR.
- *Use a short, dim moonlight period only for viewing, because true overnight darkness is better for coral and fish rest than running bright blue channels all night.
Keep a clean backup log for test day.
The Printable Reef Logbook gives you water testing, dosing, maintenance, and livestock worksheets you can print or save as a PDF.