Questions on Cyanobacteria and treatment methods

[ahill3780]

Hey everyone,

Its been a while since I last posted here on RC but I figured its high time for me to get back into things.

I am currently trying to research Cyanobacteria in marine aquariums and how to treat tanks with problems in this area. I wanted to ask for any information that you guys can supply for my research.

My general questions I am trying to gather answers on are the basics:

What is Cyanobacteria?

What are the typical causes for its appearance in marine aquaria?

What are some methods and practices an aquarist can use to avoid outbreaks?

And what steps can one take to treat a tank with a cyano outbreak?

Any information you can provide will help me in my research and I thank you for anything you can offer.

-Aaron

[Paul B]

This is actually an easy one but may require a long explanation that I will try to make simple. Red algae or Cyanobacteria is not algae but a bacteria. Having said that we must understand that there are two processes going on in our tanks (or any body of water) all the time. Oxydation and reduction. This is called Redox and is measured in milivolts. The higher the reading, the purer the water is. Freshly mixed seawater reads about 230 and anything under that means that the water is not as pure as when it was mixed. As things start to decay and algae and microbes die the redox lowers. When it gets low enough cyanobacteria will grow. It is a sure sign of deteriating water conditions. Red algae or cyanobacteria contains carotenes which are anti-oxidants, they prevent oxidation. Anyway that is not too important in this forum (And I am a little sketchy on it myself) but to defeat it you have to raise the redox level. This can be acomplished a few ways. We can remove some of the reducing compounds like dying algae, clean filters to remove rotting organic matter or the best way by using a strong oxidative agent. Ozone is the strongest thing we can use in an aquarium. Ozone is used up as it oxidizes organic material. As a matter of fact, if there is any free ozone in water it means it has the highest redox level possable because it is not being used up burning organics. As good as that sounds we do not want that situation because ozone will also burn the gills of fish and attempt to oxidize our corals thereby killing them.
We want to use ozone in a skimmer where all the ozone will be utililized in the skimmer and none of it will be released into the tank. If enough ozone is used there can be no red algae because the redox is too high.
That is the reason "Chemi Clean" will kill cyanobacteria. It is an oxidation agent like ozone and it will raise the redox. Hydrogen peroxidide will also as will bleach (but don't use that) Thats how bleach works, it oxidizes organic compounds which many stains are.
It is rumored that high water flow will kill cyano, it will not.
Have a great day.
Paul

[Randy Holmes-Farley]

There are different commercial treatments for cyanobacteria around. I am not sure what they all are. Some are antibiotics and some have unstated ingredients and mechanisms.

My preference is to deal with cyanobacteria by reducing nutrients (nitrate and phosphate especially, but also including organics by skimming, ozone, carbon, etc) and increasing water flow.

[ahill3780]

Thank you both for your input. I have been surfing around and reading through pages concerning cyanobacteria and I have to say that there is much more to learn about this than I first thought! I have tried to focus my search on cyanobacteria as it occurs in marine environments but even then there are tons of material to sift through.

So far what I have gathered seems to support exactly what Randy suggests - eliminating Phosphates and nitrates, as well as DOC from within the water column.

I have also read that the lighting in the aquarium can be part of the problem. Which makes sense considering that photosynthesis is one of the mechanisms that the bacterium uses to fuel its growth. I have read that the specific ranges of 560 - 620 nm is where these organisms are most active, but that they also do well in the ranges of 665 - 680 nm. How does this equate to aquarium bulbs? Does this mean that a brighter/whiter bulb would be better to stunt the growth of cyano than a bluer actinic bulb?

I would expect that if you could eliminate the available nutrients then the lighting would be inconsequential, and you wouldn't really need to consider it beyond noting that it may be time to change out your bulbs because of age.

I am a little confused on the oxydation point however. I have read that cyano bacteria, through photosynthesis, produce oxygen as a byproduct. Would this not help to raise oxydation within the environment, or am I not seeing the bigger picture here?

At this point I have gathered the following to be the standard for preventing cyano in the marine aquarium:

1) Make use of RO/DI filtered water as your source water for the aquarium.

2) Maintain good water quality through routine maintenance, water changes, and the use of a Protein Skimmer to reduce the levels of DOC in the tank and to aid in oxidation of the water.

3) Provide good circulation throughout the tank.

Is there anything else that should be added?

Thank again for all you input!

Aaron

[reefnetworth]

red-legged hermits love cyano, manually remove the longest (cyano) pieces slowly and dip your hand into cold tap water before re-entering the tank for more removal if necessary. have a great day.

[Paul B]

If you do as Randy said, remove nitrates and phosphates you will be raising the redox. If you reduce DOC (disolved organic compounds) which is a catchall phrase for just about anything that you put in the tank that can rot, It's the same thing as I said. You can reduce these by using a skimmer and basically adding less food which will be DOC, part of which is phosphates and the rest will become nitrates. You can call it DOC, nitrates, phosphates or Redox but it is all a part of diminishing water conditions. Even if the food is eaten by the fish it will still eventually become DOC and will need to be removed one way or another. Ozone can shortcut the entire nitrate cycle by oxidizing DOC before it can be changed into nitrate by bacteria.
Good morning Randy.
Paul

[pk1]

I have no proof that this is the case in my particular situation, but I think a few days of chronic low PH (7.5-7.6 at night) was the cause of my last outbreak. From what I gather, phosphate binds to calcium easily enough-low PH causes it to dissolve somewhat and the phosphate gets released back into the water column for the cyano to feed on. Am I reaching here? Probably, but I did nothing different in my tank husbandry to have the outbreak, that's the best guess I could come up with. I would guess that in a closed environment like my tank(previously without a GFO reactor), and with the amount of feeding I have done for 4 years, enough phosphate had ample time to bond with all the calcium based material in my tank (LR, LS etc). Maybe someone here who knows a bit more about water chemistry can tell us if this is a possibility or not??

[ahill3780]

Ok Paul, I think I follow you know, it makes perfect sense. Thank you for that explanation. I was aware of DOCs and what all they encompass, but I did not know that ozone would negate the nitrate cycle through oxidation.

Ok, heres where I show my newb side. When you say ozone I assume you mean the introduction of dissolved oxygen. Am I thinking too newbie here? What is the best way to introduce Ozone into the tank, and are there any negative effects if used incorrectly in the tank?

Sorry if the subject is getting old, just trying to understand this as best as I can. Thanks again for all you guy's help and contributions thus far. I believe I am getting a handle on this.

Aaron

[Paul B]

Ozone is not disolved oxygen (I never heard of that) Ozone is just oxygen with an extra electron. You do not want to introduce ozone into the tank. That would be disastrous. You want to introduce ozone into a skimmer. Then the ozone would be "used up" before it reached the tank but to be sure you should run the water through carbon before it returns to the tank. Many people use a controller which adjusts the input of ozone according to the Redox. We should not depend on ozone to make up for our sloppy aquarium huspandry practices. It is a tool and it has a use in this hobby but you should let the nitrogen cycle progress by alowing bacteria to grow to keep up with fish load. I use ozone because my reef is very old and there is a lot of trapped detritus that I will never be able to eliminate. I also experiment with different animals that really shouldn't be in my tank. A properly run reef should have a high redox level determined by the amount of animals present and the amount of food given through the intervention of bacteria and the mechanical export of excess nutrients. Red algae or cyanobacteria does not grow in a tank with pure water. IMO it will grow in almost all very old tanks due to the presence of trapped wastes that accumulate under rocks that are overgrown with corals and can't be moved. It grows in new tanks because the nitrogen cycle is not up to par with the animal load. It is often said that cyano needs nitrogen to appear. this is true but there is no such thing as a tank with absolutely no nitrate. The nature of the nitrogen cycle forces nitrate to be present if only for a short time until it gets converted by bacteria to nitrogen gas or is eliminated by water changes.

Paul

[bertoni]

http://reefkeeping.com/issues/2006-03/rhf/index.php

That article discusses ozone. It's the first in a series of three, if you're interested in trying to run ozone. Chemically, ozone is O3, as opposed to the normal O2 that we breathe to get oxygen. Ozone is much more reactive than oxygen.

[Paul B]

Sorry, I did not mean to go into ozone on a cyanobacteria thread. I get carried away. Jonathan, thanks for the link to that article and thanks Randy.
Here is a link to a cyanobacteria site if you are interested.
Paul
http://fig.cox.miami.edu/Faculty/Dana/cyano.html