Cyanobacteria (Red/Orange Slime, Blue Green Algae) in Aquariums, as well as related studies in this bacterial plague affecting lakes and other natural bodies of water and how this research can relate to aquariums.

Treatment suggestions for saltwater and freshwater aquariums
(including the relationship with lighting)
Updated 6/23/10

This article starts off with a generalized section about Blue- green algae (Cyanobacteria) blooms (mostly in lakes), then goes into more depth about Cyanobacteria and finally aquarium applications/treatments.

FOWARD FROM GENERAL RESEARCH (not necessarily aquariums):


First, I have dealt with Blue- Green Algae (Cyanobacteria) many times in my Aquarium Maintenance business over the years, and the key is eradication is cutting off and understanding the root cause of this. We have a lot of Blue Green algae problems in the lakes here in Oregon (it is not even a true algae, rather modified bacteria; Cyanobacteria). I understand that the out breaks have differences from aquariums, but there are similarities too. I did research on this subject (including reading the local newspapers about treatment and control in our local lakes).

A few points that were made several times both from Aquarium Research and General Cyanobacteria Research:

[1] Lighting; more research seems to also indicate that the type of light effects the growth of Cyanobacteria. In fact effective PAR light that has less in the yellow nanometers bands of light may be one of the major factors in Blue/Green, Red Slime Algae growth in slat and freshwater. In experiments with Fluorescent lights, changing to 6500 K lights reduced the amount of Cyanobacteria.

As well have noted that many freshwater lake Cyanobacterial outbreaks happen around June and July in more northern latitudes (often around the 45th parallel) which also seems to indicate a lighting factor here as northern latitudes will be more affected by seasonal changes in light than middle latitudes.
Cyanobacteria, utilize light in regions such as the low infrared. These bacteria make use of the unusable light discarded by the plant kingdom, in this case, light outside the PAR range required by plants, which is why Cyanobacteria thrive in lighting conditions that include the more yellow 4000 K and below and why actinic as well as balanced light in the 6400 K range (full sun, high Photosynthetically Active Radiation).
Research has shown that while most plants, green /brown algae utilize light at 435nm and 675nm (again the primary “spikes” in PAR), Red Slime Cyanobacteria (& other Red True Algae), utilize more of the middle yellow and green light spectrum that is most common poor fluorescent and incandescent lighting; this is an important point as you will see next.

Update 1/06/10!
A study I have been conducting (although limited) with a marine tank that has a history of Red Slime Cyanobacteria, whereby this tank has been running with fluorescent 10,000 K & Actinic lights (Coralife); was then switched to Full spectrum LED lights and the immediate result was the elimination of the Red Slime Cyanobacteria (& increased growth of green algae). This shows a direct correlation between Red Slime Cyanobacteria & lighting (at least in marine aquariums)!

For this reason it is important to improve your overhead lighting (especially marine aquariums!), in particular the type of output. Get rid of the mid range color output (many fluorescents, even power compacts still have much of this mid range yellow light) and increase strong daylight with; Aqua Ray LED Lights and/or Metal Halide.

The newer VHO, SHO daylight, or T2 daylight is still an improvement over older style T8 & T12, especially when full spectrum 6400-6700K lights are used (not the 10,000 K often recommended), However, as my tests showed even switching out with these more advanced fluorescent lights did NOT achieve the dramatic results that the LED lighting produced (only slight improvements).

In saltwater aquariums, the simple improvement in overhead light, good vacuuming procedures and addition of UV Sterilization (properly installed though) rid the tank of this problem most of the time in my experience.

With ponds, make sure opaque awnings that might block UVB while primarily allowing yellow and green light spectrums are not used.

For further information about lighting, please read this article: “Aquarium Lighting”


[2] Heat/ Water Flow; high summer temperatures, and poor in flow and out flow of water seem to induce an outbreak. This also may relate to the Redox Potential (Balance), I recommend reading more about this here:
THE REDOX POTENTIAL IN AQUARIUMS (& PONDS); and how it relates to proper aquatic health
Fresh water and good Redox Balance seems to play a role (from my own research and other research articles I have read). In lakes this bloom will usually coincide with poor inflow and outflow of water. This also causes a change in trace element content as well as Redox.
This can then be applied to aquariums (even though we are generally dealing with different Blue/Green Algae) in that maintaining regular water changes, a GH over 100 ppm (for calcium and trace elements) as well as the correct Redox Balance (UV Sterilization helps here too). Applying this knowledge can be an important part of the Cyanobacteria eradication puzzle as some of my observations/experiments have shown increased Cyanobacteria when a balanced Redox and certain mineral ions are removed from the aquarium environment.

[3] Nutrients; the amount of nitrogen based and phosphate nutrients need to be reduced.

As this relates to aquariums, I would increase circulation, clean and vacuum the bottom every other day, cover the aquarium from light for three days, reduce the temperature, consider UV Sterilization to kill free floating spores, and reduce the nutrient level.
Here is an internet source for some of this information I read:
www.spea.indiana.edu/


CYANOBACTERIA BASICS;


Knowing more about this “algae” is important for eradication;

Though cyanobacteria do not have a great diversity of form, and though they are microscopic, they are rich in chemical diversity. Cyanobacteria get their name from the bluish pigment phycocyanin, which they use to capture light for photosynthesis. Phycocyanin is a Phycobilins are useful to the organisms which use them for soaking up light energy.
They also contain chlorophyll a, the same photosynthetic pigment that plants use. In fact the chloroplast in plants is a symbiotic cyanobacterium, taken up by a green algal ancestor of the plants sometime in the Precambrian. However, not all "blue-green" bacteria are blue; some common forms are red or pink from the pigment phycoerythrin. These bacteria are often found growing on greenhouse glass, or around sinks and drains. The Red Sea gets its name from occasional blooms of a reddish species of Oscillatoria, and African flamingos get their pink color from eating Spirulina.
Whatever their color, cyanobacteria are photosynthetic, and so can manufacture their own food. This has caused them to be dubbed "blue-green algae", though they have no relationship to any of the various eukayotic algae. The term "algae" merely refers to any aquatic organisms capable of photosynthesis, and so applies to several groups.
Cyanobacteria are aquatic and photosynthetic, which means, these bacterium live in the water, and can manufacture their own food. Because they are bacteria, they are quite small and usually unicellular, though they often grow in colonies large enough to see. Blue Green Algae (Cyanobacteria) can look a lot like other true algae, however when it grows on the sides, decorations, and substrate of aquariums it has a much more “slimy” mat appearance and will easily “brush off’ or even come off with a medium to strong current (this is generally not the case for true algae). Cyanobacteria (Blue Green algae) often is not even green, but red or to a lesser degree, brown/ red or even orange. These different color variations are due to Phycoerythrin, a red protein from the light-harvesting phycobiliprotein family which is present in Cyanobacteria.

When in free floating form (more common in lakes than aquariums), it will often form a very dense green cloud that may look like paint floating on the water. Some blooms may not affect the appearance of the water. As algae in a Cyanobacterial bloom die, the water may smell bad.
Cyanobacteria are from the phylum Cyanophyta of Bacteria that obtain their energy through photosynthesis. They are often still generally referred to as blue-green algae, although they are actually prokaryotes (organisms without a cell nucleus) like bacteria.
Prokaryotes usually unicellular, although some are capable of forming cell groups called colonies. Individual Blue-Green Algae that make up these colonies will usually act independent of one another. Colonies are formed by organisms that remain attached following cell division, often through the help of a secreted slimy layer that we often see as slimy green mat in our aquariums.
Cyanobacteria are the only known group of organisms that are able to reduce nitrogen and carbon in aerobic conditions. The water-oxidizing photosynthesis is accomplished by coupling the activity of photosystem (protein complexes involved in photosynthesis) PS II and I (Z-scheme; the light-dependent reaction, which converts solar energy into chemical energy). In anaerobic conditions, they are also able to use only PS I — cyclic photophosphorylation — with electron donors other than water (hydrogen sulfide, thiosulphate, or even molecular hydrogen) just like purple photosynthetic bacteria. Cyanobacteria also have the ability to reduce elemental sulfur by anaerobic respiration in the dark. A unique aspect of these organisms is that their photosynthetic electron transport shares the same compartment as the components of respiratory electron transport. It is the thylakoid membrane (the site of the light-dependent reactions of photosynthesis) hosts both respiratory and photosynthetic electron transport, while the plasma membrane contains only components of the respiratory chain.

Cyanobacteria, nitrogen and ammonia:

Since Cyanobacteria have been around before photosynthesizing plants and before there was any free oxygen in the air, it is thought that Cyanobacteria developed the ability to scavenge nitrogen from the atmospheric dinitrogen gas often dissolved in water. Nitrogen is one of the building blocks of amino acids and necessary to living organisms. However, even though nitrogen makes up four-fifths of the atmosphere, it is locked away. Cyanobacteria are able to break apart the molecule of dinitrogen and capture the nitrogen gas via Nitrogenase enzymes. Nitrogenase enzyme molecules are very large, complex enzymes, built of two twisted and balled-up proteins, that combine and recombine to convert a molecule of N2 to two molecules of usable ammonia, NH3. Though Nitrogenase enzymes enable conversion of atmospheric nitrogen so that it can be employed in life processes, it is ineffective in the presence of oxygen. To protect the Nitrogenase from oxygen, many nitrogen-capturing Cyanobacteria (usually of the filamentous variety) have developed special nitrogen-fixing cells called Heterocysts encased in thickened cell walls. Because of this ability, low nitrate levels are generally not the key to stopping this plague.

Here is reference site about bacteriolgy that I found both interesting and useful:
THE DIVERSITY OF METABOLISM IN PROCARYOTES

TREATMENT (eradication);


With some of the above information in hand, one can now make more informed choices about how to eradicate Cyanobacteria.

*30% water change (or more) using a Gravel Vacuum (especially to remove nitrogenous waste producing mulm than often accumulates under rocks or UGF plates). Also check canister filters and wet dry filters in particular for organic mulm buildup that will eventually add nutrients to the water column, this cuts off one source of nutrition.

The use of a re-circulating Micron Filter such as the Aquarium Cleaning Machine is especially useful for removal of both mulm and the BG Algae (Cyanobacteria) itself (I will generally “scrub” the algae of rocks, etc. first and then run the machine on re-circulate mode through its 30 micron filter cartridge to remove most of the loose algae and much of the nutrient producing mulm as well.

Removing hydrogen sulfate producing anaerobic bacteria in freshwater is important as well, so make sure and vacuum all the dead spots. Along this line of thought, removing sand and replacing with gravel has helped in aquariums I have monitored with BG algae.

With Ponds, make sure sludge buildup on the bottom or in filters (especially barrel or waterfall type filters) is limited.

*Improve aquarium lighting to include more actinic and daylight and less of the yellow/green visible light. Lights around 6400 K are best, especially high output lamps, while standard incandescent lamps will allow more Cyanobacteria growth.
Consider T2 daylight lights and fixtures or Compact Fluorescent lamps that easily fit into most standard incandescent fixtures.
Better yet, is the use of Full spectrum LED lights or Metal Halide Lights as tests have shown total elimination of Cyanobacteria (providing other parameters to control Cyanobacteria are correct). When you consider that a LED light is good for 50,000 hours vs. a VHO Power Compact such as the Current USA that is only 8,000 hours; the price is actually less.

*Electrolytes and minor elements such as magnesium and calcium positive mineral ions.
Wonder Shells are useful for this in both freshwater aquariums and ponds (not usually marine aquariums)

*Add a UV Sterilizer (Very effective but not always cost effective for small aquariums, but is worth mentioning, not just for sterilization, but for Redox which plays a role in controlling bacterial BG algae). The key for UV Sterilization to be effective is for proper installation with a well designed unit, not a poorly designed unit (often sold by some retailers). Make sure your flow does not exceed 30 gph per watt (less is better) and that you have a good flow pattern in your aquarium and finally that you regularly clean any areas of BG algae build up to dislodge it.

If you have a UV Sterilizer, make sure to change your UV Bulb/Lamp every six months (possibly once per year in cool climate ponds), otherwise this device will basically become a useless “decoration”.
As well many UV Sterilizer/Clarifiers used in ponds are incorrectly installed at flow rates that at best can control “free floating algae”, but not bacteria which require 30 gph per watt or less to be effective (this is often the result of false advertising by so many UV Sterilizer manufactures).
Please see the article below on UV Sterilization which has a section and “table” about the subject of flow rate:
UV Sterilization

*In marine aquariums the addition of Mexican Dwarf Hermit Crabs (Clibanarius digueti) can vastly cut down on Cyanobacteria growth. These crabs are extremely efficient.
Here is a quote: “I had several rocks which had Cyanobacteria red slime algae covering them from the old system. The morning after adding the crabs I witnessed "Herds" of about 6 or 7 crabs each that would concentrate on a rock at a time, totally eliminating the Cyanobacteria I have never heard of a Cyanobacteria eating critter like this and it seems they actually prefer it! A week later, my tank was almost completely free of red slime”. For more about these crabs, please read this out side article resource: “Natural Red Slime Algae Control for Reef Aquariums”

*Improve the Redox Balance; this is often missed, however this MAY be part of the equation (the evidence is far from conclusive as of the last update of this article whether Redox plays a role in in Cyanbacteria growth or not). For more, please read this article:
THE REDOX POTENTIAL IN AQUARIUMS (& PONDS); and how it relates to proper aquatic health

*Cut back on nutrients in the water column by the use of RO instead of tap water in marine aquariums and in ALL aquariums cut back on feeding and improve food quality by feeding more digestible foods (No TetraMin). Better choices: Ocean Nutrition, HBH, Aqueon, Hikari, Spirulina 20 just to name a few. This again will cut back on nutrients.
You want to aim for less ammonia (not necessarily nitrates due to the properties of Cyanobacteria), which is the result of poorly digested food

*Increase circulation and dissolved oxygen. These Prokaryote Bacteria do not do as well in a well oxygenated/ circulated environment (remember my points about the lakes). This is often a major problem of ponds with Cyanobacteria outbreaks I have observed.

*Temperature; although this by itself will not make much difference, lowering your aquariums temperature (below 76 F) has been shown to help when part of an over all plan for BG algae removal or prevention.

*Medication; Copper at a level of 15 to 20 ppm is effective in inhibiting effective photosynthesis. Erythromycin (such as API Erythromycin) has shown to be a very effective medication here as well.
Please note that Erythromycin can and will destroy your nitrifying bacteria if over used, as well the use of Erythromycin is a short term solution for eradication of Cyanobacteria (especially in ponds) and the use of this antibiotic to control Cyanobacteria will often put your aquarium and especially pond in a vicious cycle of requiring more of this antibiotic as the loss of nitrifying bacteria and subsequent poor water quality results in an even better environment for Cycnobacteria growth.

The fact is that Cynobacteria thrives (in part being an ancient life form) in environments that higher plant, fish, and even other true algae cannot and why would you want to produce this environment (despite the plethora of poorly researched “cut & paste” websites and blogs that so often suggest the use of Erythromycin!).

Filtration; removing nutrients that Cyanobacteria thrive on can also help win this battle, this is especially important with ponds, which my experience over a few decades (via many house calls for algae problems) has shown to be all too common.
A simple Veggie; Bog Plant Filter can often make the difference for many under filtered ponds (as per nutrient removal)

*Lighting; turning off lights and/or covering the tank, although this is often recommended for the eradication of Cyanobacteria, this is often not effective and the BG algae bounces right back. The reason is as stated above that Cyanobacteria have the ability to reduce elemental sulfur by anaerobic respiration in the dark.
Better is to have the CORRECT lighting such as higher output 6400K lights or better, LED or Metal Halide.

CYANOBACTERIA IN MARINE AQUARIUMS:

In saltwater aquariums, Cyanobacteria are often red and appear as a red slime, thus the term “Red Slime Algae” used to describe this in marine aquariums. This NOT to be confused with coralline algae which is indicative of a healthy marine aquarium (see this article about marine chemistry necessary for the growth of coralline algae: “Aquarium Saltwater (marine) Basics”
In Marine Aquariums dissolved organic carbon is the result of anything organic that has died off and gets decomposed by bacteria. Dissolved organics are a food source of the bacterial side of the Cyanobacteria (Red Slime Algae). Sources of this dissolved carbon can include dead algae, bacteria, digested or uneaten food, metabolic waste, and some organic aquarium additives.
Aquarium additives, such as alkalinity controllers, contain bicarbonates. Bicarbonates convert into CO2, thus adding to the carbon levels. This also explains why Cyanobacteria are a common problem in saltwater aquariums.
As with Freshwater, limiting dissolved organic carbon can help, but the bacteria-algae is capable of consuming all the carbon needed derived from CO2. It is therefore important, especially for marine aquariums, to ensure a proper gas-off by water movement and adjustments of water flow. The more oxygen created, the better the degassing effect.
Filtration such as a well maintained (frequently rinsed) filter can reduce organics and thus carbon. Skimmers are effective tools, but need to be maintained frequently. The Berlin Method that combines mud filtration or a Refugium is also beneficial along with UV Sterilization.

Further Reading/References:
*http://www.ucmp.berkeley.edu/bacteria/cyanointro.html
*http://tolweb.org/Cyanobacteria/2290/2006.03.10
*http://www-cyanosite.bio.purdue.edu/taxon77.html
*http://www.ucmp.berkeley.edu/bacteria/cyanolh.html
*Algae Light Requirements
*Ultraviolet Sterilization



By Carl Strohmeyer