Something strange.

Question
just a couple of days ago I noticed that a kind of brown-
colored layer of (something that looks like dirt), was
starting to grow and grow all over the bottom of my reef and I
am starting to get concerned about it.
what is going on?

Answer
Hi Aristoteles,

What you are experiencing is an overgrowth of brown algae, this is caused from high levels of silicates in your aquarium water.

Below is some documented information, to give you some insight:

The silicates the Brown Algae requires to grow can enter your tank through several avenues, which could include: Commercial sea salts, tap water used for top offs, fish foods, and the substrate you may have on the bottom of your tank.

The source of the silicates must be identified and eliminated first, in order to get rid of the present brown algae bloom and prevent future outbreaks.

Check the source of any builders sand, play sand or other substrate materials in your tank which did not come from the ocean. There is a possibility that they may contain silicates which are leaching into your tank water.

Use only (RO) Reverse Osmosis Water or (DI) Deionized Water or RO/DI water whether you purchase an RO/DI unit or purchase RO/DI water from a commercial source.

Check to see if your commercial sea salts contain high levels of nitrates. If the salt mixture contains unacceptable nitrates, consider changing mixtures.

Removing the silicates alone from your tank will eliminate the Brown Algae problem. But, as long as you are getting your tank in order, you might as well get used to dealing with nitrates. This would be a good time for you to establish a good tank maintenance routine which includes keeping nitrate levels at a minimum, especially if you plan to have invertebrates and/or a reef tank, which do not tolerate high levels.

(Recommended)

Purchase and use Mangrove Plants in your tank or sump.

Check to see if your commercial sea salts contain high levels of ammonia/nitrogen.

Purchase and use a good "nitrate sponge".

Do not overfeed your tank.

Siphon the brown algae and uneaten food and other loose material (detritus) from the substrate.

Perform periodic water changes.

By reducing the nitrate and silicate levels, your tank will soon be healthy and free of the Brown Algae. Many of your tank occupants (corals and other invertebrates) will also benefit from the reduced levels.

I wish you luck with all your future saltwater aquarium endeavors.

Best Regards,
Dave

All Experts - Editor

http://www.ocreef.com - Director