Kelp Forest: Monterey Bay Aquarium

Brown Algae belong to the Phaeophyta group and consist of about 3,000 species, mostly are seaweeds.

Their results from the dominance of a xanthophylls pigment, which masks other pigments including chlorophyll.

Colors range from pale beige to yellow-brown to almost black.

The most common is called kelp. They are the largest algae and can grow greater than 200 feet. Some forms come attached to live rock when purchased.

Brown Algae on Live Rocks

Like the red algae, brown algae are beneficial for saltwater aquariums.

Causes and Solutions for brown algae

They begin as brown patches on the gravel and/or glass, then quickly covers most surfaces of the saltwater aquarium with a thin, dark brown coating.

It can easily be removed and wiped away. They are common in a newly set up aquarium. It is usually caused by too little light, an excess of silicates, an abundance of nutrients, and too little oxygen.

Silicates can build up through tap water that is high in silicic acid, and silicates that leech from some types of substrates.

Wipe off the surface and siphon the gravel during partial water changes. You can also use silicate absorbing resin in your filter. If you increase the lighting, they will inhibit re-growth.

When placed in your filter, chemical filter media, such as Poly Filter and Phosphate + Silicate Magnet, will remove silicates, phosphate and organic waste materials.

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For larger aquariums there are other solutions like a protein skimmer or Reverse osmosis (RO) unit that will remove chemical nutrients directly from your source water.

As your saltwater aquarium matures, they should be eliminated naturally by plants and green algae competing for nutrients.

As with any algae, keeping the tank clean and performing regular water changes is one of the best preventative measures.

Unfortunately, it is still possible to get algae in spite of regular maintenance, especially in a newly established aquarium.

Prompt attention to sudden algae growth will prevent more serious problems.

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