Chaetomorpha Macro Algae (Chaetomorpha linum) | Live Saltwater Refugium Algae

Chaetomorpha Macro Algae (Chaetomorpha linum), commonly called "chaeto," is a hardy, fast-growing marine macroalgae prized by reef keepers for its ability to absorb nitrates and phosphates from saltwater aquariums. Tumbled in a refugium under good light, a clump of chaeto becomes a natural nutrient sponge and a thriving habitat for copepods, amphipods, and other beneficial microfauna.

Pair it with the rest of our saltwater aquarium supplies to keep your reef stable, clean, and full of life.

Why Chaeto in Your Refugium

• Nitrate & phosphate export — pulls dissolved nutrients out of the water column as it grows.
• Copepod safe haven — the tangled fronds shelter pods, breeding food for mandarins, wrasses, and corals.
• No sand bed needed — unlike most macros, chaeto is non-rooted and tumbles freely.
• Reef-safe and pest-free — does not go sexual or release spores like Caulerpa.
• Easy to harvest — simply pull off a handful when it overgrows.

Care Guide

• Placement: refugium, sump, or display with low flow that keeps the ball gently tumbling.
• Lighting: a basic refugium light (full-spectrum, 6500K, or red/blue grow LED) for 8–24 hours daily. Reverse photoperiod with the display tank is ideal for pH stability.
• Flow: moderate, indirect — enough to keep the clump moving slowly without shredding it.
• Temperature: 72–82°F.
• Salinity: 1.024–1.026 specific gravity.
• Maintenance: harvest a handful every 1–4 weeks once it fills the space.

Specifications

Compatibility

Reef-safe. Will not be eaten by most reef fish. Tangs, foxfaces, rabbitfish, and some angels may pick at it — fine in a refugium where the algae is protected. Provides excellent habitat for amphipods and copepods, which become live food for mandarins, scooter blennies, and corals.

Recommended Pairings

• Bulldawg Copepod Mix — seed your fuge with live pods that breed in the chaeto.
• Bulldawg Reef Juice Elite Phytoplankton — feed the pods, feed the reef.
• Saltwater Refractometer — keep salinity dialed in for healthy macro growth.
• Reef Juice NO3 & PO4 Eliminator — pair with chaeto for tougher nutrient cases.
• Browse all saltwater supplies.

FAQ

What size is each variant?
Small Clump fits in your hand; Tennis Ball is roughly fist-sized; Large Clump is a generous softball-sized portion ready to seed a medium refugium.

Do I need a special light?
Any refugium-grade full-spectrum or red/blue grow LED works. Common picks are dedicated refugium pucks or 6500K shop bulbs.

Will chaeto go sexual like Caulerpa?
No — that's one of its biggest advantages. Chaeto stays vegetative and won't crash your tank.

How often should I harvest?
Whenever it fills more than half the refugium space, pull off a handful. Removing chaeto exports nutrients out of the system.