How much light does Chaetomorpha need?

High light, around 60–100 µmol·m⁻²·s⁻¹ of PAR. Watts are not comparable between fixtures; PAR is. If the manufacturer does not publish PAR, pick one band lower than the tank depth suggests.

Does Chaetomorpha need CO₂?

No. Marked "not needed": it grows normally in a tank with no CO₂ at all. These are usually slow growers that are also forgiving about light.

What water does Chaetomorpha want?

22–27 °C, pH 8–8.4, 7–12 dGH. At 5 dGH wide it is one of the more forgiving ranges.

How fast does Chaetomorpha grow, and where does it go?

Growth rate: fast. Placement: background / floating. Substrate: no substrate needed. Difficulty: beginner.

G-02 / 23Marine

Chaetomorpha线藻

Chaetomorpha linum · Cladophoraceae

The refugium workhorse that grows as a loose tangle rather than rooting anywhere.

Illustration to come

G-02 / 23 · Chaetomorpha Chaetomorpha linum

SpecificationsPlant atlas

Name: 线藻
Scientific name: Chaetomorpha linum
Family: Cladophoraceae
Origin: Intertidal flats and quiet bays of temperate to tropical seas worldwide
Light: High light
PAR: 60–100
CO₂: Not needed
Hardness: 7–12 dGH
Growth: Fast
Placement: Background / Floating
Substrate: No substrate needed
Level: Beginner

Water requirementsMarine

Temp.22–27 °C

pH8–8.4

Salinity1.023–1.026 SG

Alkalinity7–12 dKH

Units: temperature in °C, hardness in German degrees (dGH / dKH), marine salinity as specific gravity at 25 °C, volume in litres. These are the values recorded for the species and do not follow the site unit switcher.

Growing notes

1It grows as a tangle and rolls itself into a ball in gentle flow, so turn it now and then to light every side.
2Eight to twelve hours of light, often on the reverse cycle to the display, grows it fastest; harvest half at a time rather than clearing it out.
3Every handful harvested is nitrogen and phosphate exported, which is the whole point of keeping it.
4It whitens, thins and even dissolves without enough light or iron, so check the light and the iron level before changing anything else.
5It tangles other algae and corals, so keep it in its own compartment and fish out anything that reaches the overflow.

Frequently asked questions

How much light does Chaetomorpha need?: High light, around 60–100 µmol·m⁻²·s⁻¹ of PAR. Watts are not comparable between fixtures; PAR is. If the manufacturer does not publish PAR, pick one band lower than the tank depth suggests.
Does Chaetomorpha need CO₂?: No. Marked "not needed": it grows normally in a tank with no CO₂ at all. These are usually slow growers that are also forgiving about light.
What water does Chaetomorpha want?: 22–27 °C, pH 8–8.4, 7–12 dGH. At 5 dGH wide it is one of the more forgiving ranges.
How fast does Chaetomorpha grow, and where does it go?: Growth rate: fast. Placement: background / floating. Substrate: no substrate needed. Difficulty: beginner.