cainechow Posted August 21, 2012 Report Share Posted August 21, 2012 (edited) So I've had my tank flooded for just a little bit now and I'm getting brown diatoms coming in and I've been doing some looking around to see what there is to know about them. So far, this is what I've found.... --------------------------------------------------------------------------------------------------------------------------------------------- What Are Brown Diatoms? Are they Algae? We recognize brown diatoms in our aquariums as brown deposits on rocks, plants, decorations and substrate. Sometimes described as slimy, it is usually easy to removed with a brush or cleaning pad. It can sometimes float around in the water causing brown water. If you read about brown diatoms on the aquarium hobbyist websites they seem to all say that brown diatoms are similar to algae, but aren't true algae. General consensus is that they are "single-cell organisms but are significantly larger and more complicated than cyanobacteria. They have cell walls containing silica." (Carl, 2012) Interestingly enough, the Wikipedia entry on Diatoms, states that they are a major group of algae (2012, Diatom, Wikipedia). They are photosynthetic and can do so on much much lower light levels compared with green algae. Diatom life-cycle, much like algae, is boom and bust. When conditions are favourable, they flourish and when conditions turn less favourable, they die back. In the wild, they tend to bloom in the early spring when there is less intense light and lots of nutrients. Later, as light availability increases, algae and plants gain the upper hand and begin to out compete the diatoms for nutrients. The shift in conditions causes diatoms to slow in growth and they tend to sink to the bottoms of the bodies of water they inhabit waiting for the next time conditions are once again in their favour. In an aquarium it might be impossible to completely eradicate brown diatoms, but we can probably take advantage of their boom and bust life-cycle to keep them at bay. Why Do I Have Brown Diatoms? High Silicate Levels: Diatoms require silicates in the water to be able to build their outer diatom shells and reproduce. Silicates can be found in tap water, substrates and additives. Nutrient Imbalance: High NO2 and low NO3 & PO4 conditions such as those at the end of tank cycling are said to be bloom conditions. This is perhaps because NO3 and PO4 are prime nutrients for plants and green algae. When they are present in the aquarium in sufficient levels, they encourage plant and green algae growth thus starving the brown diatoms. Additionally dissolved organic compounds also contribute to diatom growth. Insufficient Lighting: Insufficient lighting perhaps only applies to planted tanks or if you want green algae. When lighting levels are high enough, the conditions favour plants and green algae. This is not to say that brown diatoms don't enjoy the light, they do, but in this circumstance, plants and green algae out compete the diatoms for nutrients. When light levels are low, plants and green algae are less competitive leaving more for the diatoms. How Do I Control or Prevent Brown Diatom Blooms? If your tank is newly cycled, "just leave them and they will go away on their own" seems to be a popular answer. Reasoning behind this is that as the tank stabilizes and the diatoms use up most of the silicate and other nutrients in the water they will eventually create less favourable conditions for themselves. This is entirely dependent on a tank's maintenance protocol, including maintenance schedule, products used to feed fish, feed plants, planting level and additives used to treat water among others. However, if a tank can't reach a condition that is unfavourable to diatom growth "by itself" then a change to the maintenance protocol will be needed. Reduce Silicate Levels Levels can be lowered by either using RO water or silicate removal chemicals. This option is often the first suggestion brought forth. It makes sense if you already have access to RO water and/or don't mind the cost of RO water or silicate removal chemicals. It quickly becomes and expensive proposition in larger tanks. Also, this solution assumes that the tank is getting silicate from either tap water or substrate or some additive. Manual Removal with Water Changes Simple manual removal of the diatoms is quite easy because they do not adhere strongly to surfaces. Usually lightly wiping glass with a scrubber or using a soft brush on plants, decorations and rocks is sufficient to dislodge the diatoms. However, this only makes the diatoms water born and can tend to spread out in your tank covering more surfaces. This is one of the arguments of the "just leave them" treatment. If left alone, the diatoms collect in patches rather than all over the tank. Pairing manual removal during a water change with the syphon at the cleaning area should help by quickly removing the diatoms as they are loosened from aquarium surfaces. If the new water doesn't re-create diatom growth conditions this technique should be a big help. At the very least it will get the tank looking clean. Water Changes Water changes might be a double edged sword. They will remove disolved organic compounds, but might introduce silicates if your change water contains elevated levels. Maintain Healthy Plants By adding and keeping healthy plants, you may be able to out compete the diatoms for nutrients. This is probably why EI dosed planted tanks tend to look very good. By keeping plants at optimal health by providing lots of light, nutrients and CO2, the plants out compete other photosynthetic organisms like diatoms and algae. The venerable Tom Barr is often quoted saying "Take care of the plants; Take care of the tank." Diatom Eating Livestock There are some livestock that will eat diatoms. Shrimp like ghost shrimps will eat brown diatoms but aren't particulary fast. Otocinclus Catfish seems to be the king of the diatom eaters cleaning many inches of tank in just one day. So Now What? Boom or bust? In the end almost every aquarium experiences brown diaoms at some time and there are a few things that can be done to take them out of the pictures. What are your experiences with brown diatoms? Do you have any tricks or protocol to prevent or control them? --------------------------------------------------------------------------------------------------------- Pseudo-Bibliography Carl. 2012, May. Aquarium Algae Contro; Brown Diatom, Hair, Marine, BBA, Green Spot & Water. Retrieved from http://www.aquarium-...rium-algae.html AquariumsLife.com. 2012, March. Brown Diatom Control. Retrieved from http://www.aquariums...-algae-control/ Wikipedia.org. 2012. Diatom. Retrieved from http://en.wikipedia.org/wiki/Diatom --------------------------------------------------------------------------------------------------------- Edited for formatting Edited August 21, 2012 by cainechow Quote Link to comment Share on other sites More sharing options...
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