# Help with Cyanobacteria



## mshi (Jan 12, 2007)

I have an "El Natural" Walstad type tank and for the last month I have had a bad problem with green mat (I am assuming is cyanobacteria) algae. It is covering the substate and plants. I keep trying to remove it but it grows back very quickly. The tank has been up and running almost 2 years with no prior problems. It is a 75 gallon tank with 7 medium to small fish (2 sunnies and the rest are minnows/shiners). It is planted with local plants (mostly watercress and ludwigia) from local lakes. I have 1 emporer filter for circulation with just some batting for mechanical filtration. The bio wheels are removed. With this filter the circulation is definetly better on one side of the tank. The only change which I am guessing may be part of the problem is my (2) 65 watt power compact hood went bad and due to financial restraints I replaced it with (2) flourescent shop lights (about 2 weeks before the problem began) with a total of (4) 40 watt bulbs (2 cool whites and 2 soft whites). I have always had the lights on for 11 hours and am continuing the same with the new lights. Any suggestions would be greatly appreciated.


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## Alex123 (Jul 3, 2008)

This is from gwapa.org. I copied and pasted the info:

Causes:
* Low nitrates - Usually present when all of the nitrogen/nitrate has been removed from the water column. While this is a triggering condition, it is also exacerbated by the bacteria itself using any remaining nitrogen.
* High organics - Overfeeding, or excess organic matter in the tank can trigger BGA.
* Old light bulbs - Sometimes present when light bulbs are no longer emitting usable light. This may be more of a matter of your plants no longer being able to out-compete the bacteria.
* Poor water circulation - Circulation is key in a planted aquarium so that no â€œdead spotsâ€� are present where nutrients have been used up locally, but fresh ones are not being recirculated throughout.

Cures:

* Increase nitrates - Dose nitrates until the concentration reaches ~5ppm.
* Add fast growing plants - this helps to out-compete the algae for resources.
* Blackout - BGA cannot survive without light.
* Excel/H202 treatment - Use a syringe to spot treat problem areas. Then manually remove dead patches.
* Erythromycin - use antibiotics at half dosage to kill the bacteria. Mardel Labsâ€™ Maracyn contains erythromycin and has been used effectively without harming most plants.


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## aquabillpers (Apr 13, 2006)

I recently had an outbreak in a mature tank after I did some pruning. I suspect that I disturbed the substrate and caused some nutrients to get released into the water column.

I cured it by dosing erythromycin in the form of Maracyn (NOT Maracyn 2). I dosed at the amount stated on the package.

The BGA was gone in 4 days. I then did a partial water change.

Bill


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## AaronT (Apr 26, 2004)

Changing the lights like you did is likely the culprit. The old bulbs were replaced by new bulbs and more wattage. Could you try removing one bulb to see if that helps?


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## Sunstar (Sep 17, 2008)

I have it in my ghost shrimp tank just now. Smells like beets. I fired a shot of hydrogen peroxide at it. That has usually helped or excel... but you are natural....maracyn (erthromycine) helps, although I never used it myself.


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## niko (Jan 28, 2004)

Just use EM, 200 mg per 10 gal. of water. Change water the next day. Repeat if needed. Works every time.

All the other "cures" don't really work.

--Nikolay


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## mshi (Jan 12, 2007)

I have added a power head on the side of the tank with the poor circulation. I am reluctant to lower the lighting because I am seeing a little better growth in the plants but will try it if things don't get better. I have tried the peroxide route. It seems to work well with other forms of algae but not so much with the BGA so if the above doesn't help I will give the maracyn a shot. Does anyone think adding additional plants would help?


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## aquabillpers (Apr 13, 2006)

mshi said:


> I have added a power head on the side of the tank with the poor circulation. I am reluctant to lower the lighting because I am seeing a little better growth in the plants but will try it if things don't get better. I have tried the peroxide route. It seems to work well with other forms of algae but not so much with the BGA so if the above doesn't help I will give the maracyn a shot. Does anyone think adding additional plants would help?


IMO, the only things that will eradicate BGA are erythromycin or a 3 to 5 day blackout. (There is more to the latter than the name applies.). I doubt that lowering the light level would do much more than harm the plants.

I tested Excel on my latest infestation and it had no effect.

If you decide to use Maracyn, be sure that it is not Maracyn 2, which does not contain erythromycin.

I've also had it go away by itself, but that was a very mild outbreak in a newly set up tank.

Bill


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## Sunstar (Sep 17, 2008)

the excel wiped out the remaining BGA in my tank after 2 weeks. I had been ODing the for staghorn at the time, and it took the BGA I had under control out. 

My actual control was a mix of removing BGA, hydrogen peroxide and pointing the powerhead down at the affected area and finally excel.


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## mshi (Jan 12, 2007)

Thank you all so much for the advice. Today I cleaned out as much of the BGA as I could and started dosing the tank with Maracyn. Hopefully this will take care of it. I am thinking of soaking my nets etc. in bleach. I am assuming this will kill any BGA spores and help prevent a re-occurance.


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## dwalstad (Apr 14, 2006)

mshi said:


> The only change which I am guessing may be part of the problem is my (2) 65 watt power compact hood went bad and due to financial restraints I replaced it with (2) flourescent shop lights (about 2 weeks before the problem began) with a total of (4) 40 watt bulbs (2 cool whites and 2 soft whites). I have always had the lights on for 11 hours and am continuing the same with the new lights. Any suggestions would be greatly appreciated.


You replaced 130 watts of (CFL) compact fluorescent lighting with 160 watts of ordinary fluorescent light. CFL gives about 2-3 times more intense light for plants, so in reality you reduced the lighting by 1/2 to 2/3s. Also, the CFL may have had more "plant-friendly" wavelengths.

The cool-white is okay. Many aquatic botanists use this for their experiments, and in one expt (my book, p. 180) it seemed to work well for aquarium plants . However, I wouldn't recommend "Soft-white". In the expt (p. 180), "Daylight" and "Warm White" fluorescent light gave very poor results. If you have to work with inexpensive lighting, I would have used 4 cool-whites. The lighting effect would be "Dog Ugly", but your plants might be better off.

I think your plants are trying to adjust to the new lighting. Plants are not growing as well, and algae often fills a vacumn like this.

The antibiotics may work by killing the cyanobacteria and give your plants some time to adjust. But the proof will be in the long-term results.


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## musrusticus (Aug 21, 2008)

My NPT's, after having a only little bit of BGA, started growing it like it was a cash crop a couple weeks ago. I just finished a blackout on my 5 gallon and it worked very well. Not a trace of the slime is left (though for how long, we'll have to wait and see). I'm currently putting my 29 gallon through the same procedure.

I would definitely recommend a blackout to anyone dealing with this stuff. It's free, which is much cheaper than a bottle of maracyn, and it definitely works if you do it right. On my 5 gallon I did a water change, put it in an airstone, and covered it with a black garbage bag for three days. Afterwards the water was a little yellowed but there was no BGA. Did another water change and everything is back to normal.


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## dwalstad (Apr 14, 2006)

I was getting a little troublesome BGA in my 55 gal using two 40 watt old-fashion fluorescent lights. Last week I switched to two 55 watt CFLs with a first-class parabolic reflector (AH Supply). The plants (especially the Water Sprite, _Rotalia macrandra, Hygrophila_) are growing like crazy. BGA has practically disappeared!

When plants do well, algae does poorly.


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