# will peroxide treatment hurt my GBRs



## Scouter (Mar 3, 2008)

I finally got my tank stable and happy enough to keep GBRs. I put in some new plants that brought in an unwelcome attack from a hair algae. My plan was to try 1.5ml h2o2 per gallon, but i dont' know if it'll hurt my fish. I have 2GBRs, 3 ember tetras, 3 threadfin tetras, 2 corys and an otto. Any thoughts on H2o2 and fish?

Thanks,
Scouter


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## doubleott05 (Jul 20, 2005)

i was wondering the same thing?


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## Green024 (Oct 26, 2009)

What are the specs of you tank? co2, lighting, filter/ powerheads, tank size? All of these must be somewhat in check/balance with each other before you can properly start fighting off algae to begin with. 

Have you first tried to manually remove the hair algae with something like a new/cheapy toothbrush? 

After you try that, I feel confident that h202 will not bother your fish if you use less than 1ml per gallon when you dose it. I have done this for a week straight, with no ill effect on green neons, clown loaches, and otos. Like excel, I believe h202 might have a ill effect on some plants, like vals.


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## davemonkey (Mar 29, 2008)

I have dosed as much as 4mL per gallon peroxide with no ill effects except to my snails. Snails showed signs of distress at 3.5mL per gallon and more. 
At these doses, you only dose on day 1, typically see things taking affect by the end of the day, and you can do a water change on day 2 or 3 if you wish, but by then all the peroxide has become water and oxygen. (The water change would be more for getting out dead organics. ) By day 3 you should see all the algae has turned red/brown.

This will harm your biological filter, so you'll get the cloudy water "bacteria bloom" for a couple days after treatment.


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## Diana K (Dec 20, 2007)

Max safe dose of H2O2 for community fish is about 1 teaspoon per gallon, or about 1.25ml per liter. 

While most of that is highly likely to break down over a day or so, the person who tested that much suggested a water change before re-dosing just to be sure.


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## Newt (Apr 1, 2004)

1 teaspoon is equal to 4.928922 ml
Kinda high imo


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## NanoTanker (Feb 26, 2011)

Just curious about using h2o2 myself. Is this 1 or 1.5ml per gallon dose based on the 3% solution you get at the drug store or the 28% solution you can get at the hydroponics or pool chemistry store?


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## davemonkey (Mar 29, 2008)

NanoTanker, I can't speak for Green024's doses, but the rest of us are referring to what you get at the drug store (3% solution). I don't think any aquarium inhabitant could survive the oxidation if you used 28% solution at these doses we are talking about...but I've been wrong before.


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## Diana K (Dec 20, 2007)

The dosing that I am talking about is starting with the 3% H2O2 that is most commonly available in American markets. I think I read that a slightly stronger (6%??) is common in Great Britain, but I may be wrong there. 

1 teaspoon is so close to 5 ml that they are interchangeable. There is more error in the actual volume of the tank than there is using 1 tsp = 5ml to dose your tank.


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