Coral Care Guide: Lighting, Flow & Water Parameters
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Healthy corals come down to stable water, the right amount of light, and appropriate flow. This guide covers the basics for soft, LPS, SPS, and non-photosynthetic corals.
Water
Keep stable reef parameters: salinity at 1.024 to 1.026, low to moderate nutrients, and consistent water chemistry. Avoid sudden changes in salinity, temperature, or alkalinity.
Light (PAR)
Coral lighting is best measured as PAR (photosynthetically active radiation), the amount of usable light reaching the coral. You can measure PAR with a meter or estimate it from your light manufacturer's charts. Typical ranges:
- 0 PAR for NPS (non-photosynthetic) corals
- 50 to 150 PAR for soft corals
- 75 to 200 PAR for LPS corals
- 200 to 350+ PAR for SPS corals
Water flow
Flow needs vary widely by species. As a general guide, soft corals prefer gentle to moderate indirect flow, while many LPS corals do best in moderate flow that lets their polyps move without being blasted directly.
Temperature
Keep typical reef temperatures of 75 to 80°F with minimal fluctuation.
Feeding
Many corals rely mostly on photosynthesis but benefit from occasional feeding with plankton or coral foods, especially LPS and NPS species.
New corals should be acclimated to your light gradually. See our acclimation guide, or shop live corals.
FAQ
Why won't my new coral open?
Newly shipped corals often stay closed for several days while they adjust. If it stays closed longer, check your water parameters, flow, and lighting, and look closely for pests.
What is a coral frag?
A frag is a small cutting taken from a larger coral colony and mounted to grow on its own. Frags are the most common way corals are sold and traded.
Do corals need to be fed?
Photosynthetic corals get most of their energy from light, but occasional feeding helps growth and color. Non-photosynthetic corals must be fed regularly.
Are zoanthids and palythoas safe to handle?
Some zoanthids and palythoas can contain palytoxin. Wear gloves and eye protection when handling or fragging them, and wash your hands afterward.