Frequent Aquarium Questions

• The algae grows back rapidly after I clean my tank. What's wrong and how can I fix it?
  
  
• What is algae and how do I get rid of it?
  
  
• How do I control or stop the growth of brown algae?
  
  
• I have green spots on parts of tank and shells (possibly diatoms?). What causes this and how do I get rid of it.
  
  
• In my salt tank I have a lot of bubbles on the rock and filters. They look like they are jellish. What is this and how do I get them to go away!??
  
  
• We have a freshwater tank and we want to clean the algae off the rocks and plants. What's the best method?
  
  
• The water in my 10 gallon tank starts turning green in just a few days. Is this algae? I have had aquariums several times in my life but have never seen the actual water turn green. What can I do to stop this from happening?
  
  
• I recently had an outbreak of what I will call red algae. All of a sudden its covering my crushed coral base and most of the live rock. On top of the live rock its become very long and stringy. I'm not sure what to do.
  
  
• I recently did a water change in my fresh water tank and after 2 days I had red algae start to grow. I was wondering if it was bad to have that kind of algae in the tank?
  
  
• I have recently noticed that the green and purple algae I had covering my rock and glass disappeared overnight. I recently treated the tank with Copper. Could this have killed off the algae, and was this algae bad?
  
  

• The algae grows back rapidly after I clean my tank. What's wrong and how can I fix it?
  
  It is normal for algae to begin to return within two weeks after being removed. Algae multiply rapidly. If, however, algae returns within a day or two, this may indicate a problem with either light or water quality. Algae requires light and nutrients to grow. If the tank receives too much light, is over-fed, or is over-stocked, algae problems will usually occur. If the aquarium is a reef tank using metal halide lighting which is on for twelve hours or more each day, rapid algae growth on the aquarium sides could be normal. You should experiment with photoperiod to see if you can strike a balance between algae growth and the health of the corals. Excessive algae growth on a live-reef structure is not normal. Good water flow and alternating flow should exist in a reef tank. Temperature may need control through use of a chiller. Algae consuming animals should be present in every reef, such as Blue-legged Hermit Crabs, Sally Lightfoot Crabs, Snails, and Urchins. Live rock structures should be built with spaces to allow good flow. Excessive light and/or water quality parameters should be checked and corrected if necessary. An over-fed or over-stocked aquarium will result in the accumulation of organics that algae feed on, resulting in rapid algae growth. Warmer aquariums grow algae faster. Fish-only tanks should be 78ºF, and reef tanks and planted aquarium ideally should be 74ºF to 76ºF. If the aquarium receives direct, or bright indirect natural sunlight from a nearby window, draw the blinds or move the aquarium! In a fish-only aquarium, lights should be on for about eight hours. If the lights are on longer, algae will return at a more rapid rate. Aquarium lights should never be on for more than twelve hours. This grows more algae and is bad for the fish. Cleaning an aquarium too thoroughly makes algae grow back faster! Leave a little algae in your tank when you clean.
  
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• What is algae and how do I get rid of it?
  
  Algae is the bane of many an aquarist. It grows. We remove it. It grows back, and then we remove it again. In spite of our tenuous relationship with the algae in our aquariums, we cannot escape the fact that without algae, none of us would be here! Photosynthetic algae and cyanobacteria produce the majority of the Earth's oxygen supply, and if those algae ever die . . . SO DO WE!
  Algae are mostly-photosynthetic organisms that sometimes resemble plants but are not plants, having no true roots, stems or leaves. Algae grow in freshwater and saltwater. Saltwater algae are sometimes referred to as "seaweed." Like plants, algae require light and nutrients to grow. We supply plenty of both in our aquariums, with several hours of aquarium lighting a day and nutrients like nitrates and phosphates from fish waste.
  Algae come in many forms. There are microscopic, one-celled algae, filamentous algae that resemble hair, algae that grow in sheets, and macroalgae that look like plants. There are even algae that live inside the outer integument ("skin") or calcium shell of some corals, anemones, and other sessile invertebrates called zooxanthellae. There are slimy-looking algae that are often not algae at all, but a colony of primitive photosynthetic organisms known as cyanobacteria. There are also very hard-to-remove little dots of green that sometimes grow on aquarium panels which also are not algae, but diatom or radiolarian colonies (microscopic, one-celled, animals with hard shells) with algae incorporated in their matrix. With all that said, let us answer some common questions right up front:

Algae growth is inevitable in an aquarium.
Algae consume nutrients in the aquarium that if allowed to accumulate, are harmful to fish. Algae can be a good thing.
The presence of green algae in an aquarium indicates a healthy environment for fish.
There is absolutely no way to completely prevent algae from growing in an aquarium, without killing the other life in the tank.
Chemicals should never be used to control the growth of true algae in an aquarium, and should only be used in rare circumstances to control cyanobacteria.
Correcting a severe algae problem requires time and patience.
Natural methods of controlling algae are the best and most effective.
Algae removal from the tank panels can be done on an as-needed basis, but no more than once a week. Removing algae involves either correcting negative water conditions to control or slow excessive algae growth, or an age-old process known as "elbow grease" (scrubbing it off!). Algae removal in an aquarium should be done only when necessary. We have seen many aquariums where daily removal of algae resulted in fish that were so stressed, most had diseases and were dying. You should never remove all of the algae from your tank. Allowing some algae to grow in the aquarium can be beneficial to the aquatic environment. When algae is removed from aquarium side panels, care should be taken to select an algae scrubber that will not hurt the finish of an aquarium. Be careful not to get gravel caught in an algae scrubbing pad where it can scratch the aquarium. Never use household cleaning pads to remove algae. They contain fungicides that kill fish.

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• How do I control or stop the growth of brown algae?
  
  You really cannot entirely "stop" the growth of any algae, green brown, or red, but with some good tank management practices, the rate of algae growth can be reduced. There is no such thing as an algae-free aquarium. An aquarium that never gets any algae growth is probably not a healthy environment for fish. Algae should never be controlled through the use of chemicals. Most algae-control chemicals work by inhibiting the reproduction of algae, and may also inhibit the growth of plants and beneficial bacteria. We have seen some disasterous results caused by over-use of algacides. These chemicals should only be used to get rid of green water or very bad algae problems, then good tank management alone should be used to prevent re-occurrences. It is important to remember that algae is a "plant-like" organism. Unlike a plant, it has no true roots, stems or leaves. Like a plant, it needs plenty of light and nutrients to grow (it already has the water). The first thing to look at is light. Aquariums should never be placed where they can receive a lot of direct or even indirect sunlight. Tank lights should be on no more than ten hours. The next factor is nutrients, and in aquariums, this means controlling nitrates and phosphates. Regular water changes and good filtration are important to eliminate nutrients. Vacuuming the gravel in a tank when doing a water change, removes many organics that decay into basic nitrates and phophates. A 25% water change every three to four weeks, or 10% a week, will help control the build-up of nutrients. As most city tap water contains phosphates, using reverse osmosis, distilled, or deionized water will also help. Using phosphate and/or nitrate removal media in a canister or power filter is also helpful. Water motion will also inhibit algae growth, as algae spores cannot settle and take "root" in an aquarium that has good circulation. Using small submersible pumps or powerheads in a tank, in addition to the regular filters will help add extra circulation to any aquarium.
  
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• I have green spots on parts of tank and shells (possibly diatoms?). What causes this and how do I get rid of it.
  
  If those green spots seem very difficult to remove, then yes, they are Diatom or Radiolaria colonies. Diatoms and Radiolaria are colonial one-celled animals that have a hard shell composed primarily of calcium and silica. These critters adhere to what they grow on and are difficult to remove. Algae grows on the shells of the colony, forming the green spots you see.
  
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• In my salt tank I have a lot of bubbles on the rock and filters. They look like they are jellish. What is this and how do I get them to go away!??
  
  You did not describe the organisms in enough detail, which forces us to either guess, or not answer at all. We will try to guess. You submitted this under the Algae Control Category, so we are going to assume that these "bubbles" are green in color. If they aren't, the following solution will not work. Green bubble algae is one of several species of Valonia algae. It can become a nuisance in reef aquariums, over-taking desirable Coraline algaes and choking out polyps and corals. The solution is to get one or two Emerald Crabs, Mithrax sculptus, which are primarily herbivores. These crabs seem to love to eat Valonia algae and have helped us clean up Valonia in several of our client's aquariums. Be careful though, as once the Valonia is gone, the crabs may start eating polyps and may need to be removed. We have used these crabs for Valonia control several dozen times, and have only had to remove them in half a dozen cases. There are several species of Emerald Crabs and the tendency to eat polyps may be species-specific.
  
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• We have a freshwater tank and we want to clean the algae off the rocks and plants. What's the best method?
  
  Remove the decorations and soak them in hot tap water with about 1/4 cup of salt per gallon, then put them in cool fresh water after about 1/2 hour of soaking. Then rinse everything thoroughly to remove any traces of salt. Most of the algae should then come off easily with a scrub brush or by simply rubbing it off with your fingers and you can rinse everything again. If you have live plants you cannot do this with them. You should get a couple of Otocinclus catfish which will clean the plant leaves for you.
  
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• The water in my 10 gallon tank starts turning green in just a few days. Is this algae? I have had aquariums several times in my life but have never seen the actual water turn green. What can I do to stop this from happening?
  
  If your water is cloudy and green in color, you have an algae bloom. You should cut back the number of hours the lights are on to no more than eight hours a day. You should buy an algacide treatment. We like Algae Destroyer by Aquarium Pharmaceuticals. Use the algacide until the problem goes away, doing 50% water changes twice a week in between treatments. Do not use algacides on a permanent basis! That will eventually kill your fish.
  
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• I recently had an outbreak of what I will call red algae. All of a sudden its covering my crushed coral base and most of the live rock. On top of the live rock its become very long and stringy. I'm not sure what to do.
  
  We deleted your tank information to shorten your question, but with those regular fluorsecent lamps, you need to change the bulbs at leats once a year and preferably every six to eight months. That could be part of the problem.
  
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• I recently did a water change in my fresh water tank and after 2 days I had red algae start to grow. I was wondering if it was bad to have that kind of algae in the tank?
  
  Red algae growth usually indicates that the aquarium has high levels of dissolved organics. However, if the problem started after a water change, it may indicate that your tap water has a high level of phosphates, which these days is not uncommon. I would recommend another water change, this time vacuuming the gravel thoroughly. If the red algae returns, you should consider adding some more filtration.
  
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• I have recently noticed that the green and purple algae I had covering my rock and glass disappeared overnight. I recently treated the tank with Copper. Could this have killed off the algae, and was this algae bad?
  
  It is not unusual for copper to kill algae. The purple stuff was more than likely a slime algae, or cyanobacteria, not a true algae at all. The green may also have been cyanobacteria, or even true green algae. The effect will be temporary and the algae will probably return. True green algae is hair-like or mossy in appearance and is a sign of a healthy tank. Slime-like algae usually indicates high levels of phosphates and/or nitrates in the water. The phosphate and nitrate levels should be tseted in the aquarium, and water changes done using reverse osmosis or distilled water to correct high levels.
  
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