# Hydrogen Peroxide in tanks?



## Daeorn (Dec 13, 2006)

I have a quick question to anyone who knows anything about it.

Hydrogen Peroxide in fish tanks? I work at a petsmart, and in the event of a power outage that lasts awhile, they say to use hydrogen peroxide basically to put oxygen back into the water.

I know, chemically, it is sound. It basically breaks down into h2o and oxygen.

They have done this one a few occasions, and its worked perfectly, no harm done to fish.

However this time I get a call saying they did it and they're losing and lost a bunch of fish - which is really terrible.

Doing some qiuck research, I also see that it reacts with Amonia and creates an excess in Nitrites and Nitrates, also putting too much over oxydizes the fish.

I want to know, does anyone have specific info on this process? 

Such as specific measurements of how much can be used safetly?
Or if its basically a bad idea all together? 

I want to compile the info and send it to corporate basically as a guide on the misuse and correct use of hydrogen peroxide in fish tanks during an outage or power failiure emmergency.

Thank you guys


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## neilfishguy (Oct 7, 2007)

http://www.plantedtank.net/forums/diy/37211-diy-oxygenator-fun-emergencies-new-development.html


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## BV77 (Jan 22, 2005)

http://www.malawicichlidhomepage.com/aquainfo/algae_peroxide.html
http://www.fishforums.com/forum/general-freshwater/13028-hydrogen-peroxide-kill-bba.html
these two articles lead me to try preoxide on my bba...and it's working...but I don't go any where close to max dosage. I've just been squirting a bit on the algae in spots at wc time.
No fish deaths as yet, and the stuff is working well for me


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## Guest (Oct 26, 2007)

It sounds to me that Daeorn is talking about using hydrogen peroxide as a source of oxygen when the power fails, not just for algae killing.

Any idea how much they were using, D? It would be interesting to compare that with the amount used to treat bba in planted tanks, where it seems to work well and safely.



> Doing some qiuck research, I also see that it reacts with Amonia and creates an excess in Nitrites and Nitrates, also putting too much over oxydizes the fish


If thats the case, then I can imagine there being some ammonia in the petsmart tanks. Also, if thats the case, nitrites can be more lethal to fish than ammonia and nitrates, so the fish deaths would make sense.


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## TheOldSalt (Jan 28, 2005)

Well, obviously, if you suddenly introduce a bunch of free oxygen to a tank, any ammonia will be very quickly oxidized. That's a good thing, so the problem is the ammonia itself. The trick, then, is to apply the H2O2 BEFORE the ammonia has a chance to build up from the reduction process. If the tanks have that much ammonia in them at the moment the power goes out, then that store has bigger problems anyway.

There used to be a gizmo on the market made just for this purpose, by the way. I can'trecall the name of the silly thing, but it was essentially a little ornamental chamber that sat in your tank, filled with H2O2, which emitted oxygen for an extended period. It wasn't exactly a big commercial success.

Have you considered O-tabs? These are simple little blocks you plop into the tank to release oxygen. They are commonly found in bait shops. It's not as impressive and suck-uppy as a spiffy report on H2O2, but it would be simple and effective ( and your report would probably be ignored anyway, based on what I know of Petsmart policy )

At any rate, your report should probably stress the importance of swift action. The tricky part will be in determining HOW swift, that is, can it be known if the power will be out for a long time or just a few minutes?

Uninterruptible Power Supply Units are probably the best solution. They remove the need for guesswork and function automatically in the middle of the night when there's nobody around to apply peroxide.


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## Daeorn (Dec 13, 2006)

The power was out for an hour and a half. Not nearly enough time in my opinion for as many fish to perish as there has been.

I'm not sure if it was an assemblage of things that happened, but we lost most of our smaller fish, which is truly a shame. 

We check for amonia and everything else twice a day. I had another person (I was at home at the time) check the water quality to make sure there had not been a rise in amonia, nitrites and nitrates - and there had not been.

Most of the time, our ammonia levels are 0. Very seldom it raises to .5 but thats everyonce in awhile.

I am basically baffled as to how - in only an hour an a half - so many smaller fish died off. This morning I found a sengal birchir dead as well, and I know they can breathe oxygen, so the system just running out of air doesn't make sense - something else must have happened and I'm not sure what.


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## TheOldSalt (Jan 28, 2005)

Well, you might have noticed the word "reduction" in my first post. H2O2 will normally just shed it's extra oxygen molecule, but hey, there are bacteria running amok in a different mode than normal, and there is the little matter of that big "H" in H2O2... just a thought.

By any chance, is there any H2S in the tank? A rotten egg smell or some blackness in the gravel will let you know pretty quickly if there is any, and if there is, which is very likely in a crowded tank, then fun things happen when you add H2O2, guaranteed to have a decidedly negative impact on fish and anything else in the tank. Any guesses what you make when you combine these two things?

Still, to have that much mortality in only 90 minutes, things must be pretty bad to start with anyway.


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