# Treating Blue Green Algae



## BettaCalledSaul (Mar 28, 2015)

So I have some blue green algae in my 5 gallon planted tank. I've seen some people talk about killing it off by adding food-grade Hydrogen Peroxide to the water.

Just wondering has anyone tried this? Is it worth it or should I buy a dedicated BG Algae treatment (for 4x the cost of the Hydrogen Peroxide)


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## Beefy (Mar 6, 2015)

BettaCalledSaul said:


> So I have some blue green algae in my 5 gallon planted tank. I've seen some people talk about killing it off by adding food-grade Hydrogen Peroxide to the water.
> 
> Just wondering has anyone tried this? Is it worth it or should I buy a dedicated BG Algae treatment (for 4x the cost of the Hydrogen Peroxide)


Many people will recommend peroxide, but I would recommend erythromycin. Far more specific to BGA, and less likely to hurt your fish, biofilter and plants.

For such a small tank, the cost is pretty small......


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## squatingdog (Jan 26, 2014)

+1 for erythromycin. it worked on me. no fish/plant death


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## Kdog (Apr 13, 2014)

Safe for shrimps too?


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## Linwood (Jun 19, 2014)

If it's in small spots on isolated leaves, consider just removing the leaf.

If it's in small spots on something you don't want to remove, I've had really good luck with H2O2 (not sure what 'food grade' is, just buy some at a drug store, usually 3%). I shoot it from a syringe, a few CC's right on the BGA with the filter off, try not to let the water move around, wait 10 minutes, turn it back on. The nice thing about H2O2 is that it degrades into water and oxygen -- nothing harmful to build up. Just keep it to small amount at a time.

If you have a lot of it I'd go with antibiotic, as spot treating with H2O2 is likely going to overdose the tank.


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## k38 (Nov 9, 2014)

I just finished dosing my 20 gal tank with erythromycin. It was quite effective. No harm to fish, no ammonia spike, no harm to Nerite snails or algae balls. Nothing else will work as well.


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## Kdog (Apr 13, 2014)

Is it safe for shrimps?


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## BettaCalledSaul (Mar 28, 2015)

I'm going to go the 3% Hydrogen Peroxide route, I can buy that really cheaply on eBay, but the Erythromycin is (I think) impossible to buy legally in the UK.


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## k38 (Nov 9, 2014)

Kdog said:


> Is it safe for shrimps?


Kdog, that I cannot answer, since I don't keep them. Sorry; maybe someone else knows.


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## Nastee (May 28, 2015)

2 weeks ago i noticed the first bit of algae. So I left the lights off today, did a little trimming, spot treated with 10cc of 3% h2o2. It's a 29gal. Just started it almost 5 weeks ago. No fish. Got the C02 going this week. Been slowly turning it down. Started EI dosing this week as well.
how long should I keep the lights out?
should I keep the CO2 off during that time? 
Should I stop the EI dosing?


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## klibs (May 1, 2014)

I have beaten BGA with H2O2 and blackout methods (not at the same time) and they both worked great.


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## Zoomy (Sep 13, 2014)

Increasing circulation also really helps. I've had small amounts in my 5g and my 50...in both cases adding aeration and/or circulation pumps got rid of it in time.


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## Nastee (May 28, 2015)

I'm running an Eheim 2211 and a new 2215 that I'm trying to cycle so circulation should be good


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## deltaphi (Jul 5, 2015)

I just picked up a bunch of java fern off someone and it's covered in some kind of algae (I think it's BGA - based on dark dark forest green colour and awful smell...)
I removed as much as I could manually and I've been floating them for a few days in a bucket of chlorinated water while I try and figure out what to do (so they're not in my tank yet). 
I'm under the impression that since this is actually bacteria, it will just transfer to my tank when I add the plants, instead of dying off?
Since I'm not at risk of harming any living thing in my tank, should I do blackout, H2O2 or erythromycin? (cheapest method preferred)
Could I just do the bleach dip instead?


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## Beefy (Mar 6, 2015)

For isolated plants, hit it hard with peroxide - java fern is very tough.


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## deltaphi (Jul 5, 2015)

Beefy said:


> For isolated plants, hit it hard with peroxide - java fern is very tough.


Ok.
I've got a 3% solution of hydrogen peroxide sitting around, what dose should I use? How long should I let it sit?

Thanks


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## Orca2013 (Oct 5, 2013)

How much erythromycin should i dose in 240l planted tank with a lots of rocks and driftwoods. Is 1000mg enough?


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## klibs (May 1, 2014)

deltaphi said:


> Ok.
> I've got a 3% solution of hydrogen peroxide sitting around, what dose should I use? How long should I let it sit?
> 
> Thanks


1mL per gallon is the max I use when spot treating algaes. Turn off all your filters / powerheads so there is no flow and spot treat as much as you can. Again I personally never exceed 1mL / gallon TOTAL of 3% H2O2. Leave the lights on and watch it burn for a half hour then turn your filters back on.


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## Doppelgaenger (Jul 20, 2015)

I recently dealt with a massive BGA outbreak, It went from a few spots here and there to looking like someone had dropped a green veil in the tank in just over 12 hours. I've managed to eradicate it though!

First off, while spot treating does work and you can kill a lot of it that way, the fact that you have BGA in the first place is possibly a sign of a much bigger underlying problem that will continue to bring back the BGA no matter how much you treat it.

In my case, I was massively overdosing ferts and having problems until I finally sat down to do the math of how much I needed to dose. Once I got the overferted water out I was able to knock down BGA within a week.

To dose the peroxide, I sucked it up using a cheap plastic eyedropper pipette and then placed the tip of it right next to the BGA and squeezed very slowly. You can see the peroxide come out and you'll probably surprised to see that the two don't mix very willingly. BGA reacts pretty strongly to the stuff and will start to fizz within seconds. Peroxide is heavier than water and will sink into your substrate and burn everything in there too.

Again, go over your methods to see if anything is amiss.


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