Hydrogen Peroxide: 3% vs 35%

In reading a bunch of threads about the use of hydrogen peroxide in hydro applications, I had a few questions. I like the fact that it oxygenates roots and also keeps the water free of nasties. Most seem to advocate the use of 35% food grade H2O2 vs the 3% variety available in your average CVS. People have reported anecdotally that there are all kinds of extra chemicals and metals that are added to the 3% H2O2 as stabilizing agents. Is this a fact, because in my research, I haven't been able to discern whether this is true or not, or obtain a list of ingredients? And if it is true, do those stabilizing agents harm plants, roots or interfere with nutrient uptake?

I would order some 35% H2O2 but I have heard that it is a watched chemical by the DEA, is this true? I see it on amazon, and people do use it for medical applications and alternative cancer therapies and such, but being on a government watchlist creeps me out. Also 35% is a bit pricey, but I guess the cost evens out somewhat due to the dilution factor.

I have been having some bizarre pH swings and so I squirted a little bit of 3% peroxide into both my cloner and main rez. I haven't noticed any adverse effects on the plants thus far other, only that it seems to raise the pH a bit. Does peroxide react with and/or break down the nutrients in a hydroponic solution?

why don't you use greatwhite, bennies, chlorine, or other ways that really work ?

I use h202 on occasion over the years in soil grows to eliminate fungus gnat larva. I just use over the counter... years of this, never had an issue.

I'd be more worried hurting yourself (35% is dangerous stuff) with higher pure concentrate, than your plant with lower percentage of store bought.

It's not something I do other than infrequently and as part of some lacking maintenance, you don't do it often enough to worry about such things. Thus far the plants always respond brilliantly.... and then I cut and kill them.

TWS said:

why don't you use greatwhite, bennies, chlorine, or other ways that really work ?

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I have used chlorine in the past and it is effective. I use the HTC pool shock to make home made Clear Rez. The only problem is that it can't be used in a cloner. It's been my experience that chlorine at almost any concentration will kill clone stems. The added benefit of H2O2 is the extra oxygen delivery to the root system. I have never used greatwhite or beneficial microorganisms partly because I run an aero system and can't have any particulants in my solution.

I did find this on a webpage about H2O2, though I'm not sure how much credence to give it:

"The 3% hydrogen peroxide you get at the drugstore is often protected from decomposing by the addition of sodium silicate, magnesium sulfate, or tin compounds. These stabilizers lock up the iron, copper, and other transition metals that can act as catalysts."

35% food grade is what I use for cleaning and fixing bad roots......didn't work for gnats for me (think they were actually RA's) but h2o2 has fixed slimy roots and dirty grow rooms for me just fine....I like the 35% because its just cheaper in the long run than buying 3% from the CVS or where ever.....one 30% gallon of h2o2 will make 10 gals of 3% h2o2.

As far as the 35% being dangerous, it is corrosive...I used today to clean mixed 10ml give or take per gallon....splashed some raw 35% on my hands accidentally, it took maybe 30-45mins for the spots where the 35% h2o2 hit my hands for it to start itching.....by the time it itches there should be a nice bleached spot.....I just finished up my cleaning and rinsed my hands off with water and they are fine now but you def don't want that shit in your eye and it will put spots on your clothes and carpet....I don't wear gloves and suggest glasses.

In a hydro setup I might use it for an oxy boost if an airstone isn't adequate but I have used in dirt to fix root rot and soil compaction.

twostrokenut said:

35% food grade is what I use for cleaning and fixing bad roots......didn't work for gnats for me (think they were actually RA's) but h2o2 has fixed slimy roots and dirty grow rooms for me just fine....I like the 35% because its just cheaper in the long run than buying 3% from the CVS or where ever.....one 30% gallon of h2o2 will make 10 gals of 3% h2o2.

As far as the 35% being dangerous, it is corrosive...I used today to clean mixed 10ml give or take per gallon....splashed some raw 35% on my hands accidentally, it took maybe 30-45mins for the spots where the 35% h2o2 hit my hands for it to start itching.....by the time it itches there should be a nice bleached spot.....I just finished up my cleaning and rinsed my hands off with water and they are fine now but you def don't want that shit in your eye and it will put spots on your clothes and carpet....I don't wear gloves and suggest glasses.

In a hydro setup I might use it for an oxy boost if an airstone isn't adequate but I have used in dirt to fix root rot and soil compaction.

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Cool, thanks man! Sorry to hear about your hands, that doesn't sound pleasant. I'm used to wearing gloves and protective gear when working with corrosive stuff like that from back in my lab days so it really isn't an issue for me. I agree that the cost pretty much evens out due to the dilution rate. I suppose you don't have to dilute it down to 3%, you could make whatever concentration works best. I would probably go for around 3% though.

What brand do you use?

Ya man your welcome no worries about my hands that was the point all it did was itch wouldn't want it in my eye though fortunately I already wear corrective lenses never had any on my lenses though I use a stainless turkey baster to handle the stuff, rinse thoroughly in case some comes in contact with the rubber bulb.

I use Mad Farmer brand....29 bucks at the hydro store.

I use a 50% version available locally.

Had some on skin, all it did was bleach it white temporarily.

It is more of a preventative than a pesticide when it comes to fungus gnats and such.
If you use some regularly it prevents fungus and the gnats can't survive without any

Adds about 100ml O2 per L of water more or less from what I have been reading (1ml 100% = around 100ml extra 02).
Sounds like a tiny amount but a fast moving river has around 14ppm dissolved o2 in it so you are really pumping the stuff in there.

Anotherlover said:

I use a 50% version available locally.

Had some on skin, all it did was bleach it white temporarily.

It is more of a preventative than a pesticide when it comes to fungus gnats and such.
If you use some regularly it prevents fungus and the gnats can't survive without any

Adds about 100ml O2 per L of water more or less from what I have been reading (1ml 100% = around 100ml extra 02).
Sounds like a tiny amount but a fast moving river has around 14ppm dissolved o2 in it so you are really pumping the stuff in there.

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Wow, 100ml per Liter! That's actually a ton. I bet roots would really thrive on that much O2.
I wonder how long that would last before it breaks down? A few days perhaps?
I'm going to see if there is a decently accurate way to measure dissolved oxygen without investing thousands in lab equipment.

What is the 50% hydrogen peroxide you use?
Do you need a special license, or can anyone buy it?
I've never seen high grade, high concentration H2O2 in any store

I buy 35% H2O2 from a chemicals supply company, same place where I buy phosphoric acid from, both products never triggered any questions on the counter, just bought them and left.I bring a plastic gallon 1/2 way full with tap water, and I use a siphon pump to fill H2O2 to the remaining gallon, there, I will have 17.5% concentration, it still is nasty to get on hands, but way less nasty than 35%. diluting it and storing for a long time doesn't seem to affect its strength, however, the gallon must have an air valve in its lid to depress the pressure inside it when it's closed. I use it at 1ml/L after dilution, prevents larvae and root rot, very nice stuff and I use it for cleaning hydroton between grows. I use it in many places even for cleaning scissors and cloning equipment, a really indispensable item in my hydro. Its cost was about 40$ for 30L 35% grade which is relatively cheap, but I get to buy straight from importer

Pretty sure the growth technologies h202 is 50% -strong stuff plants shock easily...what is your intended use for the stuff? Cleaning? Oxy boost? Preventative?...
Bennies are the go..be aware that H202 can kill the good bennies..meaning frequent inoculation..

Scroga said:

Pretty sure the growth technologies h202 is 50% -strong stuff plants shock easily...what is your intended use for the stuff? Cleaning? Oxy boost? Preventative?...
Bennies are the go..be aware that H202 can kill the good bennies..meaning frequent inoculation..

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Intended uses are everything you described. I'm all in favor of bennies but I was under the impression that they are more for organic style hydro grows. Also I don't know if they work for aeroponics. I do DWC as well but I basically just run H&G or Dutch Master sometimes, both non-organic, but clean solutions. What bennies would you recommend? I'm open to experimentation.

zem said:

I buy 35% H2O2 from a chemicals supply company, same place where I buy phosphoric acid from, both products never triggered any questions on the counter, just bought them and left.I bring a plastic gallon 1/2 way full with tap water, and I use a siphon pump to fill H2O2 to the remaining gallon, there, I will have 17.5% concentration, it still is nasty to get on hands, but way less nasty than 35%. diluting it and storing for a long time doesn't seem to affect its strength, however, the gallon must have an air valve in its lid to depress the pressure inside it when it's closed. I use it at 1ml/L after dilution, prevents larvae and root rot, very nice stuff and I use it for cleaning hydroton between grows. I use it in many places even for cleaning scissors and cloning equipment, a really indispensable item in my hydro. Its cost was about 40$ for 30L 35% grade which is relatively cheap, but I get to buy straight from importer

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Man you are lucky! I wish I had a chemical supply company like that near me that wouldn't ask me a zillion questions if I tried to walk in and do that. Sounds like they have a H2O2 frosty machine with unlimited refills lol! One question though, if you make a 17.5% H2O2 solution, and then dilute that to 1 mL/Liter of water, your concentration will be 0.0157%. Is that right? Because that's almost nonexistent in solution. Maybe it still gets the job done though, but it sounds quite low.

I feel the same way, I think it's just handy stuff to have around; like you said for cleaning equipment, media etc without the harshness of bleach and with the added benefit of extra oxygenation. I'm sure you'd find even more uses for it just for things around the house. I bought a steam cleaner, originally to get rid of spider mites, and now I can't believe how useful the thing is for everyday applications.

Redoctober said:

Man you are lucky! I wish I had a chemical supply company like that near me that wouldn't ask me a zillion questions if I tried to walk in and do that. Sounds like they have a H2O2 frosty machine with unlimited refills lol! One question though, if you make a 17.5% H2O2 solution, and then dilute that to 1 mL/Liter of water, your concentration will be 0.0157%. Is that right? Because that's almost nonexistent in solution. Maybe it still gets the job done though, but it sounds quite low.

I feel the same way, I think it's just handy stuff to have around; like you said for cleaning equipment, media etc without the harshness of bleach and with the added benefit of extra oxygenation. I'm sure you'd find even more uses for it just for things around the house. I bought a steam cleaner, originally to get rid of spider mites, and now I can't believe how useful the thing is for everyday applications.

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the recommended dosage of H2O2 is 1% H2O2 3% grade, which is 1/1000 35% aprox, I use it 1/2 strength and it works great in keeping the system algae free and no smells at all. I don't see the benefit of using it at high doses except maybe if you had big problems you want to cure. when I want to clean the growrocks between grows, is a different story though, then I flood the rocks with water and add a lot more than 1ml/L I dont measure I just add a lot lol I let it sit overnight, then I drain it into my res to clean the whole system then out to drain, I flush the rocks and grow on, never had problems with past grow remains this way. it is really indespensable for me to have it. As for the chemical suppliers, I advise you to look in the phone directory of your area for importers/exporters of sulfates, chlorides, acids and so on. these are used by many types of industries and are widespread but sometimes finding them is a pita for a retail buyer as they sell wholesale and usually are located in offices in buildings and not in known locations in street shops.

Redoctober said:

Wow, 100ml per Liter! That's actually a ton. I bet roots would really thrive on that much O2.
I wonder how long that would last before it breaks down? A few days perhaps?
I'm going to see if there is a decently accurate way to measure dissolved oxygen without investing thousands in lab equipment.

What is the 50% hydrogen peroxide you use?
Do you need a special license, or can anyone buy it?
I've never seen high grade, high concentration H2O2 in any store

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It's a food grade 50% specifically for plants.
I live in South Africa, I could probably get 100% without an issue (if I wanted such a volatile chemical in my house).
Our laws on many things are a little more lax than America (and much more harsh on other things).

zem said:

the recommended dosage of H2O2 is 1% H2O2 3% grade, which is 1/1000 35% aprox, I use it 1/2 strength and it works great in keeping the system algae free and no smells at all. I don't see the benefit of using it at high doses except maybe if you had big problems you want to cure. when I want to clean the growrocks between grows, is a different story though, then I flood the rocks with water and add a lot more than 1ml/L I dont measure I just add a lot lol I let it sit overnight, then I drain it into my res to clean the whole system then out to drain, I flush the rocks and grow on, never had problems with past grow remains this way. it is really indespensable for me to have it. As for the chemical suppliers, I advise you to look in the phone directory of your area for importers/exporters of sulfates, chlorides, acids and so on. these are used by many types of industries and are widespread but sometimes finding them is a pita for a retail buyer as they sell wholesale and usually are located in offices in buildings and not in known locations in street shops.

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I see what you mean about the dilution. I have used the 3% grade, and I think I might have done it a little too unscientifically. I didn't measure it out, just squirted some (not a lot) from the bottle into my rez and into my cloner. The pH went up a lot but the plants haven't responded negatively in any way.

A chemical supplier would be a handy thing to have but I doubt I'll find one. I did find this brand which looks pretty good. I cant tell if there is silver added to it or not, there might be: http://www.lefoods.com/products/498

Just as an aside, have you ever used a little bit in a bath as a soak with some Epsom salt? It's supposed to be really good for you, and oxygenate your body and blood stream. I'm interested to try it.

Redoctober said:

I see what you mean about the dilution. I have used the 3% grade, and I think I might have done it a little too unscientifically. I didn't measure it out, just squirted some (not a lot) from the bottle into my rez and into my cloner. The pH went up a lot but the plants haven't responded negatively in any way.

A chemical supplier would be a handy thing to have but I doubt I'll find one. I did find this brand which looks pretty good. I cant tell if there is silver added to it or not, there might be: http://www.lefoods.com/products/498

Just as an aside, have you ever used a little bit in a bath as a soak with some Epsom salt? It's supposed to be really good for you, and oxygenate your body and blood stream. I'm interested to try it.

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yes this is it, food grade, with no stabilizers as the product in your link mentions. however, 27$/32oz is a total tipoff! I mean I got 35liters for 45$, this lasts for years and I haven't noticed any degradation over time. I never noticed Ph going up when I add peroxide.
I never yet used epsom salt to bath...

twostrokenut said:

35% food grade is what I use for cleaning and fixing bad roots......didn't work for gnats for me (think they were actually RA's) but h2o2 has fixed slimy roots and dirty grow rooms for me just fine....I like the 35% because its just cheaper in the long run than buying 3% from the CVS or where ever.....one 30% gallon of h2o2 will make 10 gals of 3% h2o2.

As far as the 35% being dangerous, it is corrosive...I used today to clean mixed 10ml give or take per gallon....splashed some raw 35% on my hands accidentally, it took maybe 30-45mins for the spots where the 35% h2o2 hit my hands for it to start itching.....by the time it itches there should be a nice bleached spot.....I just finished up my cleaning and rinsed my hands off with water and they are fine now but you def don't want that shit in your eye and it will put spots on your clothes and carpet....I don't wear gloves and suggest glasses.

In a hydro setup I might use it for an oxy boost if an airstone isn't adequate but I have used in dirt to fix root rot and soil compaction.

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Hey! just found this post, hope you still around after all this time. I was going to use hydrogen peroxide to control a fungus gnat problem, but i found the 30% solution and i was thinking to use it instead of the 3%. What do you mean by RA's? and how do you deal with gnats if the peroxide didn't work? Im running a hydroponic system with 100 Liters and i read that i should mix 1 part 3% h2o2 to 3 parts water, but i was going to ask your recipe for the 30% h2o2.