Brown Algae needs light (your tank lights are perfect) and food (nitrates and silicates) to survive. The cure for Brown Algae is the same as the prevention: Starve it into oblivion.
Nitrates can be introduced into an aquarium not only as the end product of the Nitrogen Cycling Process (ammonia/nitrite/nitrate), but also via some brands of commercial sea salts and tap water. You can scroll down to see methods for reducing nitrates.
The silicates the Brown Algae requires can enter your tank through several avenues: Commercial sea salts, tap water used for top offs and make up and the substrate you may have on the bottom of your tank.
If you did absolutely nothing to your tank, the Brown Algae would eventually consume the silicates present and die of starvation. Since you can't do absolutely nothing to your tank, the source of the silicates must be identified and eliminated, 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 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.
Nitrates will always be something to contend with in your tank. For fast, immediate reduction, you can do a water change, using the Instant Nitrate Reduction Method. This will reduce your nitrates at the fastest rate, using the least amount of time and water. This will also get your nitrates down to a workable (10 mg/L area) level but it is only a Bandaid and does nothing to remove the source of the nitrates. Siphon out as much of the Brown Algae as possible. You will probably find that you will have to use several other methods (many of which are part of a good Aquarium
Maintenance Routine) to keep your nitrates in check. If you have a protein skimmer in your aquarium system, you might find that using the "Vodka Method" of Nitrate Reduction works quite well.
- Use only RO or RO/DI water whether you purchase an RO/DI unit or purchase RO/DI water from a commercial source. (Recommended)
- Purchase and use Mangrove Plants in your tank or sump. (Recommended)
- 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 uneaten food and other loose material (detritus) from the substrate.
- Perform periodic water changes.