Algae Guide
This algae guide is mainly aimed at the high light tank being dosed by Estimative Index.
| Black Brush Algae, BBA | |
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| Description | Often grows on leaf edges of slow growing plants, bog wood and mechanical equipment. Also sometimes it grows in fast flowing areas of the tank. Grows in clumps or patches of fine black tufts up to about 0.5cm long. |
| Cause | In a high light tank it is an indication of low or fluctuating CO2 levels or not enough water circulation around the plants. In a low light tank it is often due to changing CO2 levels. |
| Removal | In a high light tank you will need to increase your levels
of CO2 and/or improve water circulation around the plants. Scrub and cut off as much as you can first. Increase levels
slowly to 30ppm or more but watch the fish to see if they are respiring
heavily. Make sure you have good water flow around the whole tank along
with some good surface movement. Adding a powerhead may
help. If you have a low light tank without CO2 injection then not doing any water changes will help. This is because tap water often has lots of CO2 dissolved in it which causes CO2 levels in your tank to fluctuate. The algae respond to this a lot quicker than the plants do. Siamese Algae Eaters are known to eat BBA so can be used to control this algae. Overdosing Flourish Excel will clear it up. |
| Blue Green Algae, BGA | |
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| Description | This isn't a true algae, but a bacteria called cyanobacteria that is able to photosynthesise. Covers everything in a blue/green slimy mat. Easily peels off but grows back again very quickly. It can smell pretty foul. It is very commonly found in the substrate and especially along the front glass where is receives light. |
| Cause | Often caused by very low nitrates. It is fairly common to have it growing in the substrate against the front glass from where it can spread. Sometimes it appears with new setups that have had light and ammonia present at some point. Dirty substrates and filters may also bring it on. Bad water circulation is another possible cause. |
| Removal | A blackout is the best method for this. Clean out as much of the algae
as you can and do a 30 to 50% water change. If your nitrates are low
then add some potassium nitrate to get levels to 20ppm. Remove CO2 and
add an airstone. Turn off lights and cover the whole tank so no light
can enter. Leave it for 3 to 4 days. No peeking and no feeding - fish
will be fine without food for this period. After 3 to 4 days remove the
covers and do a 30 - 50% water change. Remove airstone and start CO2. You
will need to dose nitrates to
keep them dropping too low again. Make sure your substrate and filter doesn't
become too clogged up with mulm and also make sure you have good water
circulation around the whole tank. Another option is to treat with Maracyn which is an anti-biotic. Seems to work well but may affect the biological filter. If the BGA is originating from the substrate place some dark tape on the glass to hide the substrate from direct light. |
| Cladophora, Blanket Weed | |
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| Description | Cladophora is a branching, green filamentous algae. Feels a bit rough and sometimes a bit gritty. |
| Cause | Low CO2. Low nutrient levels. |
| Removal | Can be very stubborn and difficult to eradicate. Make sure your dosing is good and keep your CO2 levels high. Manually pull out every bit you can see until it stops growing. May take a while but should work eventually. Make sure water circulation is good. Overdosing Flourish Excel may clear it. Amano shrimp sometimes eat it. |
| Diatoms, Brown Algae | |
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| Description | Forms in brown patches on the glass, substrate and plants. |
| Cause | Usually found in newly setup tanks due to silicates and ammonia as the filter and substrate have yet to mature. |
| Removal | Can be vacuumed out or wiped of the glass with a soft cloth. Usually disappears after a few weeks when the tank has matured. Otocinclus will eat it. |
| Green Dust Algae, GDA | |
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| Description | Forms on the glass creating a dusty appearance across the glass. Sometimes so bad you can't see into the tank. |
| Cause | Low CO2. Low nutrients. Quite common on new setups. |
| Removal | Easily removed with a magnetic glass scraper or similar. Often reappears very quickly. Allow the algae to run its full cycle by leaving it well alone for 3 weeks. It may become unsightly but just bear with it. Then scrape it all off and do a large water change. Sometimes requires a second treatment to fully clear and leaving it for 4 weeks. Recommended to slightly reduce dosing during treatment. |
| Green Spot Algae, GSA | |
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| Description | Forms hard green circular spots on the glass and slow growing plant leaves. |
| Cause | With Estimative Index low phosphate levels often bring on a GSA outbreak. Low CO2. Also too long a lighting period doesn't help. |
| Removal | If dosing Estimative Index increase phosphate levels by adding monobasic potassium phosphate or
fleet enema solution. Aim for a level of 2 to 3ppm. Check CO2 levels. Can be scraped off
the glass using a razor blade or a good magnetic glass scraper. Between
9 and 10 hours is plenty of lighting time for the plants. If it is more
then reducing it may help. If dosing a lean dosing method like PMDD or PPS-Pro then modifying the NO3 to PO4 ratio normally helps. A bit of trial and error may be required. |
| Green Water | |
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| Description | This is a unicellular algae. Water goes cloudy. Sometimes just a green tint, other times it can look like pea soup. |
| Cause | Ammonia is often the main cause green water. There may have been an ammonia spike that isn't detected with test kits. Other possible causes are an imbalance of nutrients and/or low CO2 levels. |
| Removal | Large water changes do not seem to always help. If there
is an imbalance in nutrients then fixing it will sometimes make it go away by itself after
a while. A three day blackout followed by a large water change will hit
it hard and sometimes may clear it. A UV steriliser/clarifier or diatom
filter will clear it up very quickly and is often the only way to clear
it. A new method is to use freshly cut 1-2 year old willow branches about 0.5-1cm in width. Place these in your tank vertically so they go from the substrate to a few centimetres above the water's surface. After a few days they will start to grow roots and the green water should start to clear. When cleared remove the branches from the water. Don't confuse this with a bacterial bloom which gives the water a white haze. |
| Hair, Thread, Fuzz, etc | |
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| Description | These are very general names for a wide variety of filamentous algae. Generally green and varying in length. I have listed some of the more popular filamentous algae under their own section on this page. |
| Cause | A range of causes including low CO2, low nutrient levels and ammonia spikes. Nothing to do with excess iron as commonly thought. |
| Removal | Can be very difficult to eradicate at times. A high plant mass with good CO2 and a good supply of nutrients along with constantly hassling the algae seems to pay off after a while. Removal by twisting around a toothbrush or similar. Overdosing Flourish Excel can help. Amano shrimps, Rosy barbs and mollies will often eat it. |
| Oedogonium | |
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| Description | A fairly short length filamentous algae that can give a fuzz look to plants. |
| Cause | Low CO2. Low nutrients. |
| Removal | Check CO2 levels. Add nutrients. Overdosing Flourish Excel can help. Amano shrimps, Rosy barbs and mollies will often eat it. |
| Rhizoclonium | |
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| Description | Strands of fine green or brownish threads which are soft and slimy. |
| Cause | Low CO2. Low nutrient levels. General lack of maintenance. |
| Removal | Increase CO2 levels and check nutrient dosing. Give the tank a good cleaning. Overdosing excel should also clear it. Amano shrimp will eat it. |
| Spirogrya | |
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| Description | Fine strands of green algae sometimes very long in length. Slimy to the touch. Under a microscope the chloroplasts are aligned in a spiral - hence the name. |
| Cause | Often appears a couple of weeks after a disturbance that causes a spike in ammonia. This can be anything from a disturbance of the substrate to a dead fish gone unnoticed. Likes high light levels and high nutrient levels. |
| Removal | Once it has appeared it can be very hard to clear as it thrives in the
same conditions as plants. Pick out as much as possible and do a three
day blackout with CO2 turned off and doing large daily water changes. Dose back with macros after
the water change. Afterwards I found normal dosing Excel also helped. Rosy
barbs will eat it if made hungry. Also try reducing the lighting. Another method to try is to try lean dosing at around 1/4 to 1/8 Estimative Index levels for a few weeks. I had good success doing this. |
| Staghorn | |
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| Description | Grows in strands that branches out. Looks a bit like deer antler. Black to grey/green in colour and sometimes has a red tint. |
| Cause | Low CO2 and/or poor water circulation. A tank with overfed fish and accumulated mulm. Dirty filter. Also disturbing dirty substrates without doing water change afterwards. |
| Removal | Check CO2 levels and make sure you have good water circulation. Reduce feeding, vacuum the substrate and remove mulm. Overdosing Flourish Excel usually helps. |
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Notes Insufficient, fluctuating or poor distribution of CO2 are nearly
always at the root of algae issues in high light planted tanks, but
measuring it can often be problematic and misleading. There are 3 common
methods used for calculating CO2 levels. |
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The most common method for measuring CO2 is by using the KH/pH tables. These can give false results especially if you have any wood in your tank. The results will tend to suggest that you have higher levels of CO2 than actual levels. This is why you often see people having in excess of 100ppm CO2. The one ph drop method involves leaving a cup of tank water standing for 24 hours. If the pH of the tank water is one point lower than the water in the cup then it is said you have 30ppm CO2. This does presume that you have 3ppm CO2 in the cup of tank water which very rarely is the case. The drop checker method uses a drop checker with a KH4 reference solution and a couple of drops of bromo blue pH solution. When the colour is green, CO2 is good, blue too low and yellow is too high. I like this method and use it as an early warning system on my tank, but it does require getting used to the colour changes. |
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| If your CO2 is turned off at night then
turn it on 1 to 2 hours before lights on. You want CO2 levels to be at
optimum levels when the lights are turned on. Check levels to make sure
that they are good and compare morning to evening figures. You need to
have stable CO2 levels through the whole of the lighting period. Seachem Flourish Excel has recently been used to fight algae issues and does seem to work very well against certain types. You can either dose as instructions or two to three times overdose for about two weeks to hit the algae hard. Excel mainly kills BBA, but also can have an effect on cladophora, staghorn and hair algae. Excel does affect some plants. The ones I'm aware of are Egeria Densa, Riccia, Vallis and Fissidens. Some people also report it affecting shrimp and ottos. Another trick is to mix 1 part Excel to 3 parts water and add to a sprayer. Do a large water change and whilst the water level is low spray the exposed algae. Leave for 5 to 10 minutes and then fill up with water. |
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Thanks to the forum members of The Planted Tank, Aquatic Plant Central and The Barr Report for allowing me to use their photos. All photo's are copyright and may not be copied. |
This page was last updated 6th May 2007
