# H2o2 dosing how to?



## Minit (May 14, 2012)

Ive read some mention of h2o2 dosing how is it done?
Thanks


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## Fdsh5 (Jan 3, 2012)

You simply squirt it right onto the algae with a syringe. I would say no more than 1 ml of h2o2 per 10 gallons of tank


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## Complexity (Jan 30, 2008)

Tom Barr recommends 1ml per 10g. I've seen many others suggest 2-3ml per 10g. I've gone into no-no land and have dosed 4ml per 10g with success. However, CRS and a few plants are sensitive to H202 so make sure what's in your tank can tolerate H2O2. I'd definitely start out at the 1ml per 10g level that Tom Barr suggests if this is your first time to try it in your tank.

Here's how I dose H2O2:

Turn off the filters (calm water allows the H2O2 to stay where you put it longer)
Using a syringe, squirt the H2O2 directly on the algae. Keep going until you've used up all the H2O2 you are dosing for the entire tank.
Turn off the aquarium lights (light breaks down H2O2)
Wait 15 minutes.
Turn on the filters (but leave the lights off).
Wait another 15 minutes.
Turn on the lights.
Many people suggest doing a water change after treatment, but I find this unnecessary since H2O2 breaks down into water (H2O) and oxygen (O), neither of which need to be removed from the tank. It can't hurt to do a water change so do what you think is best.

The reason I prefer to run the filters 15 extra minutes with the lights off is to allow the H2O2 to circulate throughout the tank, including the filtration. This helps kill the algae all over the tank instead of just the one area you spot treated. While you'll still need to spot treat areas with more severe outbreaks of algae that you missed the first time around, areas with just a trace of algae can get treated through the "whole tank method" of being circulated throughout the tank. I think this helps clear the algae out all the nooks and crannies.


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## Forumsnow (Feb 22, 2012)

http://www.barrreport.com/showthread.php/10147-H202-as-algae-killer here he suggests 1ml per gallon. H202 is having no effect on my thread algae. Good luck


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## jcgd (Feb 18, 2004)

BBA or blue green algae (cyanobacteria) are usually what it works for. BBA will turn pink and then to dust and as the peroxide breaks down it turns into water and oxygen. The oxygen kills the BGA. I actually just dosed my tank a few minutes ago, ended up injecting it into the soil a bit under patches of cyano. As it bubbles oxygen it seems to kill the BGA off. You can watch it happen.


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## plantbrain (Dec 15, 2003)

While I do suggest lower dosage, I also suggest hitting it daily.
Then a water change.

Hitting something 1x per day.........4 days in a row...........at lower dosage vs 4mls/10 gal all at once is much more controllable. It also does not harm livestock or any plants, including moss. It does not toast the algae quite as well, but the water changes and other aspects are beneficial.

But over 4 days, (or more I suppose), you can really kick and target most any species of green algae that otherwise is a PITA. 

Plants respond very well to daily large water changes.

This method does not cure any algae issue, but the water changes will help you address the CO2 or other issue. IME, green algae is almost always a CO2 issue, as is BBA if the CO2 is really bad. 

Milder stuff under higher light: green algae.

Mr Podio has a decent write up on the method:
http://www.aquarticles.com/articles/plants/Podio_Algae_Hydrogen_Peroxide.html


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## Lurch98 (Oct 7, 2011)

Crossing my fingers trying this. I've had some battles getting my CO2 right the last 2 months, and I keep having hair algae and BBA pop back up. I tried to treat with Excel, and treated my Fissidens to get rid of all the algae growing in it. I assume from the "nuclear holocaust" look of my previously lush fissidens that it is very sensitive to Excel. 

Oh well, this hobby keeps me interested while I learn. One can read and soak stuff up like a sponge, but there's always more to miss and learn by mistake.  Crossed fingers for some 1 mL/gal H2O2 magic!


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## Complexity (Jan 30, 2008)

Be gentle with the fissidens. I'm not sure how tolerant it is of H2O2. I've never tried it myself and my internet searches give conflicting reports.


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## In.a.Box (Dec 8, 2011)

I just put 30ml in a 40B, I'm kinda blind so I tho I saw 1ml per gallon.
Lucky I stop myself and re-read this page again. Almost put another 10ml in there.
No water change, fish doing good.


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## Complexity (Jan 30, 2008)

1ml per gallon is correct. So a 40g tank can be dosed 40ml of H2O2. That's the low, "safe" dosage.

I've put as much as 4ml per gallon in my 90g tank (meaning, I dosed 360ml in my 90g tank) with great success. I'm not suggesting that you use such a high amount, but saying this only to illustrate that 40ml in a 40g tank is fine.

However, since there are varied reports on how fissidens handles H2O2, it's probably best that you started out trying 30ml on the first attempt. Give it a few days to see how the fissidens responds. If it's okay, then you can repeat the dosage. If it's not okay, then you'll have to decide what you want to do from there.


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## nat72sherman (Feb 20, 2012)

If my bba is on a plant. Can I take that plant out and pour h2o2 on it? There so much ancillary things to buy with this hobby, I'm kinda tired of shelling out money. esp for something like a syringe.


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## Complexity (Jan 30, 2008)

You can get an oral syringe at a drugstore, such as Walgreens, for around $2.50:

http://www.walgreens.com/store/c/walgreens-oral-syringe/ID=prod6001629-product

I would not suggest pouring H2O2 directly onto a plant out of the water because now you're talking about 100% pure concentration, not mixed in tank water. You can easily damage you plants this way, costing you more than the $2.50 you were trying to save by not buying a syringe.


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## hamato (Jun 7, 2008)

I took out any plants that were too covered in algae to treat effectively in tank and put them in a bucket with water and about 3ml/gal of h2o2 for around 30min. I would not use pure as it will probably just kill your plants, but you can dose higher than normal as you will not be concerned about fish.

As for the syringe, I told the person behind the counter at my local drug store I wanted to buy the cheapest one they had and she just gave me one for free.


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## PlantedRich (Jul 21, 2010)

I would think there would be quite a large supply of free items to squirt a bit of h2o2. Somebody in health care might correct me but is there a lot of stuff which can only be used once which would work for this? I'm thinking like ear syrings used on kids ears. Are those type things used once and tossed? 
Maybe not a real big savings if one has to make a special trip to an office as compared to picking one up while you are at the store already.


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## _endgiggles (Oct 5, 2021)

This is a super old thread, but I hope this finds someone well.

Let's start with my tank: it is a 1 year old planted, dirted, 55 gallon tank. I have about 2 inches of miracle gro potting soil with a cap of about an inch of eco complete. It is moderately planted with a variety of crypts (too many to name). I had 15 tiger barbs, 5 neon tetras, and 1 juvenile rainbow shark at the start of the dosing.

The dosing: I was extremely reluctant about doing this, but frequent water changes were doing nothing for me and my algae situation, so I gave in to the pressure and dosed 40ml's of 3% hydrogen peroxide directly into the water column. I did not turn off my light, wavemaker, canister filter, or improvised hang on back breed box converted into aquaponic grow bed. (Read the last part twice slowly if it didn't make sense, about as best as I can break it down LOL.) I let this go for about 6hrs. After the first hour, the water got extremely cloudy and the fish started to slow down in movement, I panicked, but I figured for science in going to push on and if need be hospital tank my fish. When I returned to my tank six hours later, the water clarity had resolved itself drastically, and the stubborn stuck on algae on my plants was gone! The algae growing on my equipment was one of the 50 shades of gray and on the die off. I couldn't believe it! While conducting a 60% water change (50% is minimum recommended) I noticed 1 barb did not make it. Now before I get heat for this, I can say there was 1 barb out of my 15 that was not doing the best prior to this dosing. I removed the fallen, and completed the water change and called it a night. When I checked on the tank the next day (approx. 24hrs after the dosing) to my surprise even more algae was gone and dying! All my fish looked super happy, my plants were standing up healthy and blowing in the current.

Two days later . . .
My fish are healthy, and the 2 that had white sores around their mouths (forget what thats called) had cleared up. My plants didn't die off, however I did have some MINOR die back. (I'm talking 1 to 2 leafs per every other plant) I did a big clean up, scraped my equipment and glass again and was able to get more dead algae off. It was a success!

Final thoughts: Let me start by saying, it is recommended to turn off all equipment while dosing hydrogen peroxide, I however never agree with this for dosing anything. My thought here, is with the moving parts in my equipment the good beneficial bacteria won't be harmed by this... for my case, I was correct. It has been 6 days and I have not had a spike in anything at all. I've been checking levels everyday, and keeping a close eye on it for clouding. My plants are still doing great, as well as my fish, in fact everything looks as happy as I think I've seen it! Since then, I added 2 Peace Lily's✌ into my aquaponic breeder box to help remove nutrients in the water column. (If anyone wants info on how to modify a hang on back breeder box to support an aquaponics system let me know and I'll work on a instructional with pictures). Anyway guys and gals, this was super long but I wanted to make sure I covered all bases clearly, before I received negative comments. Cheers!


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