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Filtration & Protein Skimmers

Refugium Guide: Chaeto, Light, and Nutrient Export Made Simple

Everything about adding a refugium to your reef — lighting, macroalgae selection, and harvest schedule.

By Saltwater Aquarium Guide Published May 10, 2026

Tangled green strands of Chaetomorpha macroalgae — Photo: Daderot, CC0 1.0, via Wikimedia Commons (cropped)

A refugium turns nutrients into harvestable algae mass and shelters pod populations. The best $50 upgrade you can make to a sumped reef.

Lighting

6500K full-spectrum or warm-white LED on a reverse photoperiod (on while display lights are off) stabilizes pH overnight.

Macroalgae choice

Chaetomorpha (chaeto) is the standard — non-invasive, easy to harvest, fast-growing.