Why do a blackout to kill cyanobacteria if it's immediately reintroduced to the tank again anyway

lazylewis

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Sep 23, 2016
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I've had severe BGA issues. I can manually remove it all (as in I can't see any left) and a few days later it's back all over the tank. I've considered the often repeated advice of a 3 day blackout, but what I don't understand is how this helps. If you remove it all manually (which is quite easy to do) isn't this the same as what a blackout would achieve? The blackout would kill off all the BGA, but then it would be immediately reintroduced to the tank ( as it's so common). Is a blackout only useful when you have something like a dutch tank where the BGA is impossible to manually remove?
 

Dennis Singh

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the only way I've fully eradicated this stuff when i've had it is antibiotics. Probably the only time i recommend chemicals compared to a natural way of removing algae. 3-5 days of dosing and its gone forever.
 

lazylewis

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strungout said:
the only way I've fully eradicated this stuff when i've had it is antibiotics. Probably the only time i recommend chemicals compared to a natural way of removing algae. 3-5 days of dosing and its gone forever.

I probably would have used antibiotics by now but that requires a prescription. And if cyanobacteria is everywhere, how can you get rid of it forever? My understanding is that even with antibiotics you would only remove your current infestation but the tank would very quickly be reinfected. If BGA is always dormant in the tank, what's the benefit of killing it completely with antibiotics?


Please be patient with me, I can't get my head around this.
 

Dennis Singh

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its not likely to come back if you dose it enough, the anti biotics, I forget which kind, will not harm plants or fish. You need to keep dosing, i disliked this algae until i discovered how to treat and it never came back. Your tank in other post is pretty nice by the way.
 

rajkm

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erythromycin is the antibiotic.


is your nitrates at least 5ppm? It gets easily triggered by low nitrates.
 

lazylewis

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rajkm said:
erythromycin is the antibiotic.
is your nitrates at least 5ppm? It gets easily triggered by low nitrates.

My nitrates are above 5ppm now, I am dosing EI. But they were zero when the BGA first appeared, I think due to using two bags of purigin.
 

lazylewis

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strungout said:
its not likely to come back if you dose it enough, the anti biotics, I forget which kind, will not harm plants or fish. You need to keep dosing, i disliked this algae until i discovered how to treat and it never came back. Your tank in other post is pretty nice by the way.

When you say you have to keep dosing, you mean doing a full dose of antibiotics? So you would dose for maybe five days or something like that?


I believe Tom Barr said you will always have BGA in your tank, and that he has it in all his tanks. That's why I'm confused regarding the benefits of antibiotics compared to manual removal or a blackout and then changing the conditions that allow BGA to flourish.


Many have said that once they used antibiotics the BGA never returns. So is BGA as common as people say?
 

Dennis Singh

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lazylewis said:
When you say you have to keep dosing, you mean doing a full dose of antibiotics? So you would dose for maybe five days or something like that?


I believe Tom Barr said you will always have BGA in your tank, and that he has it in all his tanks. That's why I'm confused regarding the benefits of antibiotics compared to manual removal or a blackout and then changing the conditions that allow BGA to flourish.


Many have said that once they used antibiotics the BGA never returns. So is BGA as common as people say?

full dose, you have to read online dosage suggestions. 5 days or more, until you see it spotless, its not likely to come back after that, but i have had a situation where it did come back, very very very lightly


i cannot comment for barr, but he seems to never get algae, or his plants take care of his types algae.
 

lazylewis

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I'm currently dosing the API Erythromycin. I'm doing it full strength for the recommended period on the package. It says 8 days. I'm on day three and I think it's working. I'm not very comfortable flushing water with antibiotics down the toilet but not sure if dumping it in the backyard is any better, maybe it is?
 

trong

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In the past I've successfully used a product called chemiclean from boyd. it's not an antibiotic so they say and it promotes good enzyme for biofilter. safe for inverts too.
 

lazylewis

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I did look at chemiclean. I couldn't find out what chemiclean was made of or how it works so I decided not to use it.
 

Julia Adkins

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You need two things going on for the cyanobacteria to be reduced to tolerable levels. The first is to remove it manually or by antibiotics. But keep in mind that you don't know all of what the antibiotics will kill off that will create another imbalance in the tank. Dumping the water in the back yard where not much grows is better than disposing of it in the sewage system. The second is to make sure that the other plants that are in your tank have an optimum growing environment. Candida albicans, also known as yeast, is a normal part of the human flora. As long as the internal environment is balanced the yeast stays within its boundaries. When you take antibiotics, this kills off beneficial as well as harmful bacteria. The competition is gone which gives the yeast an opening to overgrow. And you have a yeast infection. Better to concentrate on making conditions in the tank better for the rest of the plants and remove the cyanobacteria manually and give the tank longer periods of darkness in conjunction with manual removal until the balance returns to the tank.
 
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lazylewis

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Sep 23, 2016
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Julia Adkins said:
You need two things going on for the cyanobacteria to be reduced to tolerable levels. The first is to remove it manually or by antibiotics. But keep in mind that you don't know all of what the antibiotics will kill off that will create another imbalance in the tank. Dumping the water in the back yard where not much grows is better than disposing of it in the sewage system. The second is to make sure that the other plants that are in your tank have an optimum growing environment. Candida albicans, also known as yeast, is a normal part of the human flora. As long as the internal environment is balanced the yeast stays within its boundaries. When you take antibiotics, this kills off beneficial as well as harmful bacteria. The competition is gone which gives the yeast an opening to overgrow. And you have a yeast infection. Better to concentrate on making conditions in the tank better for the rest of the plants and remove the cyanobacteria manually and give the tank longer periods of darkness in conjunction with manual removal until the balance returns to the tank.

Hi Julia,


I agree with what you're saying, and that's why I fought the bga for over a month. I completely manually removed it twice a week. I made adjustments to my nutrient dosing. I shortened the photo period to 5 hours. I increased flow and added a skimmer. I increased oxygen at night. I only turned to the antibiotics because I'm out of ideas. Each time I made a change I gave it a week to see if there was a decrease in growth of the BGA, but it never even slowed it down.


The weird thing is I'm was getting good growth under the bga. The stem plants shoot up to the surface so fast I feel I'm constantly trimming them. One set of leaves gets covered in bga so a new set shoots out above. My monte Carlo carpet would literally break through the bga to get light if I didn't clean the bga off for a few days.


It was an imbalance that caused the outbreak. But once it's taken over it seems impossible to recover buy manually removing it. It's all gone now after a full dose of antibiotics, so will be interesting to see if it comes back.
 

Gwendelion

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I fought BGA for years in one of my tanks. I did multiple blackouts and multiple rounds of antibiotics. The antibiotics appeared to leave me with a strain of BGA that was resistant to them, as it stopped working after I think the second course. The only thing I found to help was what's called the "one-two punch" outlined here: http://www.plantedtank.net/forums/23-algae/203684-one-two-punch-whole-tank-algae-treatment.html


I did that about two years ago and it cleared up all my algae problems, and allowed me to get my tank balanced out. I do still have a colony of BGA lurking in the substrate, but it only starts to emerge a couple times a year when the seasons change, I think due to light and temperature changes, when I just squirt it with some H2O2 before it gets a foothold.


I hope this helps, BGA is one of my least favorite things.