# Blue Algae



## Nordic (Nov 11, 2003)

Is it bluegreen algae ? that slimy stuff?

I thought thats a type of bacteria which is best killed with medicine...


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## zhima (Dec 23, 2003)

this is my friend's algae pblm, is it blue-green?


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## SCMurphy (Oct 21, 2003)

Are you using your CO2 consistently? 
Are you dosing a nitrogen source? 
Do you have access to Maracyn, it is an "aquarium medicine" essentially erithromicine (an antibiotic), which will kill off a gram negative bacteria like BGA which is a cyanobacteria. 

BGA is a controvertial bugger, we argue about what causes it and how to treat it. The "medicine" will knock it down but doesn't ensure that it won't come back. That requires fixing the problem that let it bloom in the first place.

The problem is that this bacteria can fix nitrogen from atmospheric nitrogen the gasseous Nitrogen that is dissolved in the water. Plants can't do this. If you tank is short on nitrates then this bacteria can function taking fertlizers out of the water column that your plants can't take up because they don't have a nitrogen source. 

The course of action I have seen work is do a water change and fertilize, treat with the Maracyn for a week (1/2 dose recommended on package), and then do a water change and fertilize, and then keep adding a nitrogen source when you do water changes or as needed based on your tank. I think Rex's FAQ covers how to keep your fertilizers in balance. 

zhima: Yes that looks like BGA. If it smells bad when you pull it out of the tank you will know for certain.


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## zhima (Dec 23, 2003)

Thank u so much Murphy!! You are so helpful!

It's not my tank, but I share a lot of aquarium growth with him, that's why I want to help him make his tank as healthy as mine.

Accordingly, he's not dosing any nitrogen or phosphate source. He uses liquid fertilizer and PC. CO2 is turned off during the night.

Will UV-sterilizer help?


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## SCMurphy (Oct 21, 2003)

I would completely avoid dosing P until you can control N and K.

UV won't affect the BGA, which brings up another point. I've heard of people using green water to out battle BGA.


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## Chuck (Dec 29, 2003)

I thank you as well for the good advice Murphy,

Same problem here... My riccia is just starting to come in nicely, and just about all my darker java moss has "contracted" this blue algea goo ??? Not to mention two other forms of algea.. Uhg... Good to know it's not really algea... I'll do the Maracyn, and recomended ferts, and see what happens...

By chance, is there any link with malicite green ?? The blue bacteria has started in pretty bad just after treating my tank for ich... Cured my little loach, but the plants didn't like it one bit....

Any progress on this thread Ace, Zhima... Are yer tanks still blue ???


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## Ace (Dec 10, 2003)

well i tear down everything and resetup and now everything is fine.


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## Splash (Feb 18, 2004)

Well, I won't get involved in the controversial aspects of the topic, but I can tell what caused in from my experience. The two times that I had major problems with blue-green algae (BGA) was when I wasn't fertilizing at all and was doing lots of water changes to keep nutrients very low. My nitrates were unmeasureable, but phosphate (from decaying fish food) was about 1-2 mg/L. Because of the low nitrate, the tank was algae free until the sudden bloom of BGA (actually, a _cyanobacterium_).

So my experience is consistent with the idea that BGA occurs when nitrate becomes limiting to higher plants and real algae, but phosphate is still available. Other microflora that usually outcompete BGA die off. BGA can fix aqueous nitrogen gas, so it suddenly blooms.

You might prevent future outbreaks of BGA by fertilizing with just a bit of nitrate so that phosphate becomes the limiting nutrient. Alternatively, you can add a phosphate-absorbing resin to your filter.




zhima said:


> Thank u so much Murphy!! You are so helpful!
> 
> It's not my tank, but I share a lot of aquarium growth with him, that's why I want to help him make his tank as healthy as mine.
> 
> ...


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## SCMurphy (Oct 21, 2003)

SCMurphy said:


> Do you have access to Maracyn, it is an "aquarium medicine" essentially erithromicine (an antibiotic), which will kill off a gram negative bacteria like BGA which is a cyanobacteria.





Splash said:


> Because of the low nitrate, the tank was algae free until the sudden bloom of BGA (actually, a _cyanobacterium_).


cyanobacteria, _cyanobacterium_, :wink: Whichever you have, erithromycin will kill it, no nitrates and existing phosphates can encourage it. Don't do the first if you aren't fixing the second. 

Who did you think you were being controversial with?


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## Splash (Feb 18, 2004)

Just facing reality. For any comment from one person in this forum, you are likely to get ten or more contradictory comments from others. Funny thing is...most or all of them are correct...there are just so many variables involved that one person's experience is likely to be different from another's.

BTW, I wasn't correcting your previous post, just reinforcing it.

splash




SCMurphy said:


> Who did you think you were being controversial with?


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## SCMurphy (Oct 21, 2003)

I understood the reinforcing part, you just confused me with the controversial part.


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## Daemonfly (Oct 1, 2003)

Oh, the controversy!

I've had exactly the same experiences as Splash described. Fixing it now with the Maracyn & getting my ferts on schedule (been lazy...)


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