Referred to as a microalgae, brown or golden algae is actually not an algae at all, but diatoms. What you are actually seeing in your tank are diatom skeletons, all linked together. It can appear as a simple dusting on the tank walls and substrate surfaces, or it can turn into a massive growth that covers just about everything in the tank. This type of algae outbreak typically occurs when a tank is just completing or has finished
the nitrogen cycling process, new live rock is introduced, as the curing process can add nutrients when some organisms on the rock dies off, or tank maintenance has been neglected. It is a normal occurrence, as diatoms are one of the first to appear in the chain when the tank conditions are conducive for algae growth, and is usually a precursor to other forms of desirable and undesirable nuisance type green macroalgae. As you can see in our
enlarged photos, the center area where the diatom algae first began growing is beginning to turn green.
What Makes Diatoms Grow and Solutions For Eliminating This Problem
We suggest that you don't try to put all of these solutions into action at one time, because if you do, when to problem subsides you'll never really know "exactly" where the problem was coming from and which solution worked to fix it. Start with one solution and see what results you get, and if that one doesn't work, try another one, and so on, until the problem is resolved. Now, i n order for all forms of algae to grow, they require only two things; light and nutrients.
- Lighting: The use of improper bulbs, lack of maintenance, and extended lighting hours are contributors that can lead to all sorts of algae problems.
- Solutions: Only use bulbs that are designed for aquarium use, paying close attention to their spectral output; don't bombard the tank with an over abundance of light, follow the basic wattage rule of thumb; run the lights 8 to 9 hours a day.
- Nutrients: Diatoms are most responsive to silca/silicates, but DOCs (Dissolved Organic Compounds), nitrates, and phosphates are food sources as well.
- Silicates are most often introduced into aquariums by means of using unfiltered fresh tap water, the wrong kind of sand or substrate material, and through sea salt mixes that contain a higher than normal concentration of this element.
- Solutions: Use RO/DI filtered make-up water, an aragonite type sand or substrate source, and a high quality sea salt mix.
- Phosphates (PO4) are commonly introduced into aquariums by means of using unfiltered fresh tap water, and through many aquarium products that may contain higher than normal concentrations of this element, such as sea salt mixes, activated carbon, KH buffers, foods, and many other sources. Also, for established reef tanks the long-term use of Kalkwasser precipitates phosphates out of the water, and these phosphate based compounds can settle on and in the live rock and substrate.
- Solutions: U se RO/DI filtered make-up water, a high quality sea salt mix, and be aware of the elements contained in other common aquarium products you may be using. For solutions to problems that can arise from using kalkwasser, refer to The Fishline's Microalgae article.
