# How to get rid of Blue Green Algae (BGA)?



## aquaquang

I own 32 gal, with 101 watts of light. The current photosynthesis period is 10 hours and my tanks has been running for 2 months now. I have a hard time to make Blue Green Algea dissappear, most of my HC are covered of them. I have to remove them by using a toothbrush every 2 days then they come back as fast as they can. That's really get me frustrated.

Does anyone know how to get rid of them?

Dosing: Plant Gro NPK, Flourish Iron, Potassium and Excel 
DIY co2


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## Homer_Simpson

(1) Manually remove as much as possible, clean filters thoroughly, increase water changes to two times a week, siphon gravel well, increase water flow/circulation. Combine with 3 day blackout. You have to stop c02 during blackout, completely cover tank, and you may have to run an airstone until blackout is complete.

(2) Another Option, treat BGA with Hydrogen peroxide as described in this article. 
http://www.gpodio.com/h2o2.asp or better yet Erythromycin antibiotic as per package instructions. This should be a last resort measure after you try and address the root cause.

(3) Test your nitrates with a calibrated test kit. Low or zero nitrates are one cause of Blue Green Algae but not the only one.

When I got BGA in my 10 gallon, I was unable to pinpoint to root cause and trying to address the possible root cause did not work in my situation, so I dosed with Erythromycin, that was 3 months ago. My biological filter, plants, or fish were not effected and the BGA has not returned(knock on wood).


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## erijnal

aquaquang, I like to do an 8 hour photoperiod on tanks that are high light. That might help in the future.

As for right now, try adding a pump or powerhead to your tank to try and increase water circulation. In the cases I've had to deal with it, BGA would always pop up in tanks with low flow. Now every one of my tanks have pretty good flow in them and I haven't seen BGA in a year. Cleaning out your filter is also a good idea if that's something you've neglected.

Also, you could try dosing Ethromycin (sp?) to kill it. It's pretty much a 100% success rate. This isn't an option if you have invertebrates in your tank, since it would kill them. Also, unless you change something, this is just a quick fix and BGA will most likely return after dosing Ethromycin.


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## exterminator

Spot treating with Seachem Excel helped me to get read of BGA. I was 3-x dosing it for about 10 days (15 ml/day to 65 Gallons) and it was gone. Try to spot treat it with a syringe (dropper).

Good water flow also helps to keep it under control.


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## aquaquang

Before doing black-out I removed all BGA as much as I can, it was a pain on $#@. Changed 25% of water, cleaned out my Filter, substrate and dosed a bit of Nitrate. I use a powerhead as DIY Co2 injection, should I turn it off during black-out?

I'm using Black-out method now, covered all my tank with newspapers. Since my tank are fully planted, I just worry that they will turn to yellow and will eventually die within 3 days without the light on.


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## trenac

The C02 needs to be turned off. I would try putting a blanket over the tank, newspaper may let some light in. Healthy plants will not die without light for a few days. You need to do the blackout for 5 days to make sure it is all gone. Here is step by step instructions... http://www.aquariaplants.com/cloudygreenwater.htm


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## MatPat

Don't worry about your plants they may lighten a bit in color and appear to have grown alot but they will be fine. People ship plants all over the country and they ae in boxex for 3-5 days and they survive.

Since you say you have HC in the tank, I would caution against a 5 day blackout. I have hears some say that 3 days can stress this plant but I've never had a problem with that. Adding the blanket over the newspaper is great advice.


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## npnailer

erijnal said:


> aquaquang, I like to do an 8 hour photoperiod on tanks that are high light. That might help in the future.
> 
> As for right now, try adding a pump or powerhead to your tank to try and increase water circulation. In the cases I've had to deal with it, BGA would always pop up in tanks with low flow. Now every one of my tanks have pretty good flow in them and I haven't seen BGA in a year. Cleaning out your filter is also a good idea if that's something you've neglected.
> 
> Also, you could try dosing Ethromycin (sp?) to kill it. It's pretty much a 100% success rate. This isn't an option if you have invertebrates in your tank, since it would kill them. Also, unless you change something, this is just a quick fix and BGA will most likely return after dosing Ethromycin.


Ethromycin killing inverts is news to me...is that documented? I've used it a couple of times, and at far as I can tell, lost nothing even so much as a small snail? Certainly, the shrimp were unaffected, and even the population of tiny copepods seemed just as prevalent after, as before. NOT arguing against the claim...but just saying that in my case, it did not affect inverts in the least.


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## Homer_Simpson

npnailer said:


> Ethromycin killing inverts is news to me...is that documented? I've used it a couple of times, and at far as I can tell, lost nothing even so much as a small snail? Certainly, the shrimp were unaffected, and even the population of tiny copepods seemed just as prevalent after, as before. NOT arguing against the claim...but just saying that in my case, it did not affect inverts in the least.


When I dosed EM in my 10 gallon with BGA, it did not effect the Amano Shrimp. He is still alive and kicking, 3 months after EM treatment. The snails that I did not know I had, I also noticed kicking around 3 months after treatment.


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## niko

Hm, strange thing someone still asks how to get rid of BGA. Erythromicyn.

1. Day1: Remove all BGA you care to remove.
2. Dose 200-300 mg Erythromicyn for every 10 gallons of water.
3. Don't worry about shrimp, too much or too little nutrients, light, the "rain in Spain".
4. Day 3: Change 25-35% of the water. Add EM again.
5. See (3).
6. Day 6: Change 25-35% of the water. Done.

Ah yes, while growing BGA take time to marvel at these creatures - they are some of the oldest known living organisms on Earth so have some admiration and respect to what you are about to kill.

--Nikolay


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## npnailer

niko said:


> Hm, strange thing someone still asks how to get rid of BGA. Erythromicyn.
> 
> 1. Day1: Remove all BGA you care to remove.
> 2. Dose 200-300 mg Erythromicyn for every 10 gallons of water.
> 3. Don't worry about shrimp, too much or too little nutrients, light, the "rain in Spain".
> 4. Day 3: Change 25-35% of the water. Add EM again.
> 5. See (3).
> 6. Day 6: Change 25-35% of the water. Done.
> 
> Ah yes, while growing BGA take time to marvel at these creatures - they are some of the oldest known living organisms on Earth so have some admiration and respect to what you are about to kill.
> 
> --Nikolay


That's where I am also Niko...
I know..you need to address the root cause, and I agree, but Etho does the deed quick and effectively, and does not harm anything else in the tank if you do water changes(to deal with the spike in dissolved organics). I've heard the argument that you can create a "super bug" version that's resistant to Etho...but is there actually any documentation of this? I would think that if that were the case, then this super variety would have already spread through the aquarium trade long ago, just due to it's very resistance(in that in tanks treated, there would be some that would get passed on to other tanks, so on, and so forth). Since this "super bug" variety apparently does NOT exist...I argue that it's not been created.


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## niko

I think I had an EM resistant BGA few years ago. I didn't have enough EM and I underdosed - like 50 mg for every 10 gallons, instead of 200-300. The BGA seemed to change color a bit - it seemed to be slimier than usual. When I treated with 200 mg EM it wouldn't go away. I just let it be and it never really spread, but lived in the tank for about a month growing slowly. Then it gradually disappeared.

I think that there is a lot going on in planted tanks that we never notice. These things can promote algae or kill them. So I think that a superbug algae has little chances of spreading because the conditions vary so much, even in the same tank.

I think that the closest to a super bug is BBA.

--Nikolay


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## erijnal

npnailer said:


> Ethromycin killing inverts is news to me...is that documented? I've used it a couple of times, and at far as I can tell, lost nothing even so much as a small snail? Certainly, the shrimp were unaffected, and even the population of tiny copepods seemed just as prevalent after, as before. NOT arguing against the claim...but just saying that in my case, it did not affect inverts in the least.


My bad, I might be thinking of something else :doh:


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## aquaquang

Since Tuesday, my tank has been used the blackout method, it looks BGA has changed color, they actually look already dead. Tomorrow morning I will take them out, vacumm the substrate and will change water.

I have 101 watts of light wich is kinda high, is it one of reason why BGA appearing?


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## prBrianpr

I have the same problem with cianobacteria, covers the top of my plants, and is mixes with hair algae. the two algae are very green. I making wather changes, the nitrates was 30 mg/l and I down to 0 mg/l (I know that cianobacteria lives with 0 nitrates) but im going to down al the nutrients of algaes, on tuesday im going to buy a phosphate remover resin. I think that 0 nitrates and 0 phosphate the algae dissapear, plus 3-4 days without light and then using exel and cleaning the aquarium. thats kill the cianobacteria or not afect it at all? if I remove manually the odor of algae is pretty stinky and I dont want to do that.


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## Homer_Simpson

prBrianpr said:


> ...on tuesday im going to buy a phosphate remover resin. *I think that 0 nitrates and 0 phosphate the algae dissapear*, plus 3-4 days without light and then using exel and cleaning the aquarium. thats kill the cianobacteria or not afect it at all? if I remove manually the odor of algae is pretty stinky and I dont want to do that.


Be careful about going down to zero phosphates and zero nitrates or you could end up with even more algae problems. Limiting these will effect the health of your plants and algae will be quick to take advantage of unhealthy plants. The idea of excess phosphates and nitrates causing algae has been debunked. The only way that I would risk not dosing zero nitrates and zero phosphates is if I was using a substrate like ADA Aquasoil. The best defense against algae is to reduce your lighting to 7 hours and split that total or try noonburst photoperiod. As far as your blue green algae goes, the excel will not work on it. Just dose Erythromycin and be done with it. Then take the proper preventative measures to keep it from returning, keep your filter and substrate clean, increase circulation in the tank, and dose nitrates and try and keep them from dropping to zero.

And use a good fert dosing regime like EI or PPS-PRO.


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## KatjaT

I have used acriflavinhydrochlorid 1% solution and it works every time


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## HTN86

Brush them off again then immediately over dose your tank with excel. I use this method to get rid of my dust algae, which is the wall version of BGA.


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## prBrianpr

I think that the algae blooms or cianobacteria is produced by a unbalance of nutrients or a lot of nutrients in the water. if the algae not have food it die, im going to put the nitrates and phospate in good levels. my father uses algae destroyer advance and it works fine and kill all algae but not kill the plants and not affect it. But im not want to use chemicals to kill the algae, I want to destroy the root of the problem. Ok im not going to low the phosphate to 0, what is the ideal phosphate? .5? im have fish that produce phosphate and nitrates that is suficient to plants.


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## longhornxtreme

I thought copper killed inverts, not antibiotics?


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## Homer_Simpson

prBrianpr said:


> I think that the algae blooms or cianobacteria is produced by a unbalance of nutrients or a lot of nutrients in the water. if the algae not have food it die, im going to put the nitrates and phospate in good levels. my father uses algae destroyer advance and it works fine and kill all algae but not kill the plants and not affect it. But im not want to use chemicals to kill the algae, I want to destroy the root of the problem. Ok im not going to low the phosphate to 0, what is the ideal phosphate? .5? im have fish that produce phosphate and nitrates that is suficient to plants.


The same nutrients that are food for algae are also food for plants, which means that if you starve the algae by depriving them of these nutrients you also end up depriving the plants of nutrients which could lead to problems. It has been shown time and time again that zero nitrates is one cause, although not the only and not always the cause of Blue Green Algae. It has been shown that in a tank with sufficient carbon via c02 injection at 30 ppm or provision of carbon through Excel, adequate light, an abundance of "healthy" fast growing plants and some floaters, and adequate but not excessive lighting, the plants will use the nutrients like a sponge and outcompete the algae for those nutrients, so even if the nutrients are there the plants will suck them up before algae can get to them. The reason that people have such success growing plants using substrates like Aquasoil even when they don't fertilize the water column is that Aquasoil leaches nutrients heavily from the substrate into the water column.

The only other way to prevent algae is to slow down plant growth, by setting up a low light, low maintenance tank, with many low light plants, then algae never forms and becomes a non-issue.

As per Rex Grigg the following are considered appropriate nutrient levels for a high tech, high light, c02 injected tank. http://www.rexgrigg.com/ferts.htm

Nitrates 10-20ppm

Phosphates 1.0-2.0 ppm

Iron 0.1-1.0 ppm

Potassium 10-20 ppm


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## prBrianpr

my tank have almost 4 watt of light per gallon. use CO2 and recently conbined with excel. have laterite and flora-max substrate mixed with inert gravel. 25% of water change weekly. fertilisant weekly. have good water flow. what could be the problem? I have cianobacteria with 30 mg/l nitrates and I low it to 0, but with the fifhes it will be going up. phosphate about 2mg/l but I want to low it to .5.


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## prBrianpr

I down the phosphates to 0 and going up again. I use excel 2x and the cyanobacteria die in 3 days.

the red algae is turning white and dying. the hair algae becomes a little problem


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## trenac

prbrainpr... Take a few minutes and read over the following on ferts: http://www.csd.net/~cgadd/aqua/art_plant_fertilizer_intro.htm
http://www.aquariaplants.com/nutrientsfertilizers.htm

You problem seems to be that you are decreasing P04/N03, when you want to keep 1ppm/10ppm of each. With 4 wpg you also want to make sure your C02 levels stay at 30ppm.


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## prBrianpr

ok I know that, but my nitrate was in 30 mg/l and phosphate in 2 mg/l and I has red algae, hair algae, back algae and a big problem of cianobacteria. thats is why I down nitrates and phosphate to 0 to kill the algae but the excel help me more. The plants never look bad and now with excel the plants are growing fast, more fast that with CO2 only


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## trenac

The point is that you need to keep consistent levels at all times of N03, P04 & other nutrients. Bottom line is inconsistency causes algae, so does a lack of nutrients. Balance is the word!


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## prBrianpr

Ok, balance is the best point to mantain a planted aquarium but, how I can make a balance?


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## trenac

You need to find a dosing regimen that works for you. In our science of aquatic fertilizer forum you will find two popular methods. The The Estimative Index (EI) & Perpetual Preservation System (PPS). Read over these a see which one works best for you.

Making sure to keep consistent level of nutrients, carbon (C02 &/or Excel) & light will keep a tank balanced.

If you read of the links I provided in the earlier post, they will guide you toward the levels you need to keep.


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## prBrianpr

ah, thankyou. I need a CO2 sistem to brings 30 mg/l of CO2 to the plants for maximum grow and less problems of algae.


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## hoppycalif

I think you can get maximum growth with less CO2, if you keep it at that same concentration in the tank every time the light is on. I suspect that 20 ppm is enough. I tried running it at that level for a few weeks but my water circulation became bad as the plants grew too much with too little pruning, so I jacked it back up to 30 ppm as part of the battle to get rid of the BBA. I haven't tried to reduce it again.

If you want to use 20 ppm instead of 30 ppm, you can use 2.5 dKH water in the drop checker instead of 4 dKH. That would give you green at from 15 to 25 ppm of CO2.


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## prBrianpr

thankyou, but now I have a fermentation system of CO2 and that only reach 18 mg/l when it reach maximum fermentation, then its concentration of CO2 goes low. I need a expensive CO2 system?


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## hoppycalif

You can get more CO2 from a DIY system by using multiple bottles of yeast mix. If you then stagger the start times of the bottles you can keep the concentration of CO2 more constant too, which helps in avoiding algae.


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## DaveS

I have fought the BGA battle in three of my tanks over the years. I found the blackout method worked as well or better than anything else I tried (tons cheaper than using EM as well). I will note that BGA will quickly come back no matter what method you use if the root cause is not addressed. In all three of my affected tanks the final solution was quite simple: increase the bioload in the tank. In the past I tended to run my tanks with light fish loads / heavy plant loads. In every case of BGA (and I had it bad in my 75g tank for well over a year) simply adding more fish got rid of the BGA for good (after a final blackout of the tank). I am guessing that low nitrates were probably my issue, and if you have a light fish load this could be your issue as well.

HTH,

Dave


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## oregon aqua

http://www.aquariumlife.com.au/showthread.php?p=31339#post31339

this link has a guy who used excel (actually using glutaraldehyde substitute) to tottaly remove bga from their tank. the pics are amazing. im experimenting on glut my self mainly because i always here about it but never see any picture prof on the web. i also want to see the long term affects of usage on the tank environment. http://forum.aquatic-gardeners.org/viewtopic.php?t=997


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## Homer_Simpson

My experience has been quite different. When I set up my experimental 10 gallon tank: http://azdhan.googlepages.com/thelostworld it was severly overstocked and nitrates as tested via a calibrated nitrate test kit measured 20 ppm when Blue Green Algae hit and every month thereafter. Having adequate nitrate levels or a overstocked tank did not keep the BGA from forming, which leads me to believe that while low or no nitrates may be one cause of BGA, it is not the only cause and some tanks with consistently adequate nitrates may still develop BGA. Just like diatom algae may have more than one cause. Cause and effect relationships are really to prove in this hobby as with all other things in life.


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## killacross

if BGA is caused by low nitrates...why not just skip waterchanges or just have incredibly small ones for a few weeks? wouldnt that cause nitrate levels to rise?


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## Seattle_Aquarist

Hi killacross,

My experience has been that once I detect BGA I want to get rid of it as quickly as possible. It spreads very quickly with the right conditions and "chokes" the other plants. Not to mention is smells awful!


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## killacross

oh i know its nasty stuff...completely took over a 10gal once...i eventually just tore the whole thing down and tossed everything in it (when it returned after the 3rd or 4th time...cant remember)

ever since...I jus went the chemical route w/o negative effects


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## Ahura-sama

Buy some dry Kno3 and dose w/ it. For 32, 1/4 teaspoon should be enough to cover the nitrate. I have same tank, 33g, and can attest to this.

Also 10 hr light is a bit much, no??


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