Photo uploaded from and property of Scubs' Adventure
One of the first types of nuicance algae's to make it's way into our aquariums are diatoms...Otherwise known as "Brown Algae" or "Golden Brown Algae". It is easily distinguished by its appearance being brownish in color (as its name suggests) and is usually seen on the top layer of your substrate (almost like a film), over your tank walls and even all over your rocks. In essense, they will pretty much cover any surface. An outbreak of diatoms usually occurs when conditions are ideal for it's growth. An example would be right after you have completed your initial cycle after setting up a new tank where there are tons of nutrients available in the water for them to feed on. Silicates in the water are their primary food source as well as they can't resist nitrates and phosphates as well. Lighting is also another important element needed for their growth.
Understanding that silicates, phosphates, nitrates and lighting all play a major role in the growth of diatoms, you will need to consider a few things to help eliminate, control, or better yet, avoid them as much as possible.
- Lighting is one thing that could be minimized a bit during an outbreak of diatoms. If there is no light, then one of it's requirements needed for its growth will be cut off from it. You can either cut down your photoperiod to a few less hours a day during this time or if you can, you can even go a few days without lights at all (granted nothing else in your tank will be effected by this). Also, your bulbs themselves can add to the problem and this goes for pretty much any algae for that matter. Certain color spectrums (usually in the lower kelvin range like 6700 and under I'd say) will be more targeted towards "plant" growth which is the reason why lights in this range are usually used in freshwater planted tanks. Also, aged bulbs will shift in their color spectrum a bit so stay on top of changing them when required to do so.
- Use ONLY RO/DI water unless your tap water has been tested and was found suitable for aquarium use. Alot of the time, tap water contains a lot of silicates, nitrates and phosphates in it that will only fuel the algae to grow. Some will recommend doing multiple frequent water changes in an attempt to flush out the "nasty water" but continuing to use nothing but tap water loaded with silicates, nitrates or phosphates will not solve anything. All you are doing is adding more fuel for the diatoms to feed on. So with that said, RO/DI water is what is needed here.
- Increased water flow can help as well. Areas where flow is lacking are areas where waste/detritus can settle. What this does if not removed is the waste, un-eaten fish food etc will rott which in turn shoots up nitrate and phosphate levels. Once again we are providing a food source for diatoms. By preventing any dead spots in your tank, it will lift all of the waste into suspension into the water column where it can be "filtered" out of the aquarium. In addition to that, increased water flow (especially at the tank's surface) increases gas exchange which means less carbon dioxide available for the diatoms to use for growth as all plants and algae use carbon dioxide as well.
- Be careful of your choice of substrate as some substrates have been found to contain silicates in it as well.
- Salt mixes and food are also contributors to adding phosphates into the water so you'd want to choose them carefully as well. In addition to that, avoid over feeding your tank. Un-eaten fish food that is not removed from the tank will only fuel your diatom problem. Some good reading on phosphates can be found here http://www.reeffrontiers.com/forums/...02/#post611239
-Manually removing diatoms with the aid of a scrapper, vacuum, siphoning tube etc is also an option. Keep in mind though that chances are if it's food source is still available in the tank, it will just continue to grow back, but I guess it would be nice to export some of the bound up nutrients the diatoms used for it's growth out of your system by manually removing the diatoms. Sometimes even just leaving the diatoms alone and just letting them run its course and work for you in a sense is also an option. Just let the diatoms grow on it's own and use up all of the available nutrients in the water until they are all gone at which point it will begin to die off. Some people actually harvest macroalgaes for this same purpose.
- Some people employ the use of critters to help consume diatoms like snails for example, but this is only a temporary fix and quite honestly, not sure how much benefit it offers as these snails etc that consume the diatoms poop as well so they are just adding nutrients back into the water so I guess it is a personal judgement call. Sometimes people look at it as "Out of sight out of mind" but personally I rather get to the root of the problem and not use critters to "mask the problem" for lack of a better term.
- Practice good tank maintenance/husbandry. This includes regularily cleaning filter floss, cartridges, sponges, filter socks etc every few days (or change them) in an attempt to remove any trapped waste that if allowed to sit and rott, will in turn result in increased nitrate and phosphate levels. Vacuum your substrate (or care for it according to it's type - ie ssb, dsb etc) regularily to remove any waste that may be trapped in it. Perform regular weekly water changes using RO/DI water and be sure that if you are using anything like carbon, that that is also changed on schedule.
- A protein skimmer is also a bonus to have running on your system as it's primary function is to remove DOC's from the water column which fuel algae to grow. If you don't have a skimmer as yet, I personally would recommend one. Not totally necessary as people run successful tanks without them, but any little thing that can help make life easier for you and improve water quality is a good route to go in my books.
The remainder of the article can be found here Diatoms