# h2o2 as algae remover



## freshreef

Ive read all about it here and in the krib and would like to give it a try. could u guys tell me from your own experience what is the side effects and if it helped u remove the algae
1. how to dose and what is the recommended dosage that i should use in a planted tank with fish n shrimps?
2. does the hydrogen peroxide help with all the algae kinds? and if yes - should i use different dosage with different kind of algae?
3. first of all would like to try it in my 30L tank that has green water more then 3 days


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## Daniel

About H2O2... I tried that in my tank, and it's only effective over the blue algae, cyano... no with nitrate-algae or another kinds... 

About dosage and aplication... 5 or 10 ml each 100 liters, it's recomended... application, just over the cyano, without mercy :twisted: 


SORRY FOR MY BAD ENGLISH! :S


See ya!!!!!

Me


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## Gomer

had a MASSIVE ..and I mean MASSIVE staghorn infestation. 2 consecutive days of 2oz (1/4 cup) into my 30g. came home from my trip 4 days later and there wasn't a SINGLE SIGN of staghorn in the tank. ..not clogging the filters, or anywhere. Didn't loose a single fish, plant or shrimp that I could tell.


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## HeyPK

I have also heard that black beard algae (another species of red algae, along with staghorn) is also very sensitive to H2O2. Have not tried it myself.


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## freshreef

thanks , what concentration did u use? i got 33% - same dosage as u mentioned? 
what about h2o2 against green water?


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## Simpte 27

I tried H2o2 on BBA. It looked up and laughed at me after bubbling for about 30 min.


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## plantbrain

H2O2 is good for a number of spot treatments I think, if you have lots of algae, best to remove it by hand first, then kill off the stragglers.

Full tank treatements might help tip a slight imbalance, but so would a tank cleaning. Add that to any treatment method BTW. 
The problem with chemical treatments with a strong oxidizer are fish and plants can be fried if you do not do precise measurements and just dump what the person thinks is a fair amount, does many treatments every few hours etc.

You can get more effective use from dosing about 2/3 of the day into the light cycle also.

Turn off all filters etc for spot cleaning.

Some folks can use this and treat whole tanks with some success if they are *careful.*

Everytime someone post a H2O2 thing, someonme tries it and kills their entire tank of fish. It's not this gentle thing. 
Same is true for copper but it's less lethal to your fish.

I personally don't use any anti algae chemicals since back in the 1990's nor need to nor really recommend them, but folks seem enamored with them and focus less on the plants. Algae killing is fun I suppose..........then it comes back, then you kill it again, then it comes back etc etc.

For spot cleaning, I just lop off the leaf or scrub it off. I use the plants and plain old mainteance methods to deal with algae.

Reagrds, 
Tom Barr


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## amber2461

Gomer said:


> had a MASSIVE ..and I mean MASSIVE staghorn infestation. 2 consecutive days of 2oz (1/4 cup) into my 30g. came home from my trip 4 days later and there wasn't a SINGLE SIGN of staghorn in the tank. ..not clogging the filters, or anywhere. Didn't loose a single fish, plant or shrimp that I could tell.


Hey Gomer

Did you have to do any water changes after the h2o2 into the tank? Some ppl tell me to have a massive water change but you mentioned nothing about it, pls help clear up this matter (pardon the pun )

Cheers


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## pineapple

I used 2ml H2O2 per US gallon on a 30g aquarium to eradicate thread algae. I dosed two days running, 60ml, midday without removing fish or turning off the filter. There were no casualties, except the thread algae which was completely gone at the beginning of the third day. Tonina sp., Anubias, Marsilea sp. all survived. The fish showed no stress.

I used H2O2 to spot treat BBA on another aquarium without much success. Spot treating is an art, perhaps, which requires a good sized long syringe. In the end removal of rocks which had BBA (without returning these rocks), cleaning of the filter tubing with H2O2, and washing the filter and media in dechlorinated water, and vacuuming the substrate carefully was the key to eradicating BBA - along with increasing the CO2 level and ensuring it was consistent (in this case changing from DIY CO2 source to pressurized supply).

Andrew Cribb


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## AV8TOR

pineapple said:


> I used 2ml H2O2 per US gallon on a 30g aquarium to eradicate thread algae. I dosed two days running, 60ml, midday without removing fish or turning off the filter.


Help me try and understand this please, you are dosing this ratio straight to your tank water? No spot treatment?

I have some brush algae (I think) growing on some slow growers such as Anubias barteri that I just cant get rid of. Would this work? I have been thinking of removing the plant for a bleach dip.

Any good (reputable) online articles on this treatment?


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## pineapple

> Help me try and understand this please, you are dosing this ratio straight to your tank water? No spot treatment?


Yes, dosing it straight into the tank water. Not spot treatment. This dealt with thread algae.

I'm not sure whether H2O2 would be effective in eradicating brush algae.

H2O2 at certain reasonable levels does not harm fish and does not require a clean up (as does bleach solutions).

Andrew Cribb


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## mudboots

I dosed the equivalent of 3ml per gallon in a 125 (about a cup and a half), dumped straight into the tank, and lost all algae except some GSA (I'm guessing that's what it is) on some driftwood. A week later I dumped 2 and a quarter cups (better than 4.3ml per gallon) straight in. The algae on the driftwood is still doing fine:mmph:. Almost all of my ramshorns and every single pond snail died#-o. Glad to see the pond snails gone, but hope the ramshorns make a bit of a comeback soon. No harm has been noticed on the plants or to the fish. 

I put a hob filter on while doing this to keep the water moving (normally have no filter) and did it when lights were going full blast.


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## mikslik

4 ml per gallon will kill pond snails? interesting... surely it would also kill shrimp at this concentration, too? Does it then become inert after a period of time? Or do you have to do water changes to cycle it out?

Mikslik


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## playthecello

Resurrected thread to the rescue... I have blue-green algae in my tank (29g) that snuck up on me and got pretty bad. I moved, and did lots of wrong things that could have caused the outbreak (neglecting setting up my diy co2 b/c it was too much trouble, not replacing my clean up cory cats after they died, thinning back my plants but not my fertilizer, letting my light bulbs get too old, etc etc...) but I didn't realize how bad it had gotten until last week when I noticed the plants weren't really growing anymore, and everything looked pretty gross. 

I spent 4 hours cleaning the goo off my plants and gravel and everything, but I can't get it all, and what escapes the gravel vac gets caught in my feathery plants. I was thinking I would have to hunt down some Maracyn until this peroxide thread showed up. Peroxide is way easier to come by than erythromycin in my area, but I know the latter is effective and relatively safe. So, what would the people with more experience recommend? 

To (partly) answer mikslik's question, hydrogen peroxide 2(H2O2) breaks down into water 2(H2O) and oxygen (O2), but I don't remember exactly what causes it. I know it decomposes spontaneously, but there are catalysts that speed it up (silver, for one). I think I remember hearing that light catalyzes the decomp, which is why it's sold in an opaque bottle, but that could be wrong. (high school chemistry was a while ago)


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## Tex Gal

playthecello - you know BGA is a cyanobaceria right?

Here's a link:
http://www.theplantedtank.co.uk/algae.htm


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## playthecello

Yep, I know that. I was hoping to get it under control without using chemicals or antibiotics, but I'm not sure if that's going to be possible. A lot of the posts I've read recommend Maracyn or other form of Erythromycin to kill it, but then I saw this peroxide thread and wondered if it would work just as well, since it works as a topical antiseptic/antibiotic. It kills nasty things in paper cuts, so why not nasty things in the aquarium?


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## mudboots

Regarding the breakdown of h2o2, I recall that light energy is the main catalyst. 

Regarding the cyanobacteria, if you try it sure enough let us know how it works. I've not really had much stuff like that to try and kill because two evil outbreaks out baterial disease popped up from "adopting" fish and I had to dose antibiotics, so everything was wiped out.

Mikslik - I'm not sure it'd be nearly as bad for shrimp as it is for snails, but davemonkey and kwc1974 had tried this and I think both of them had shrimp at the time??? I might be mistaken...


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## playthecello

I tried the peroxide. I dosed 2ml/gal two days in a row. The algae looks a lot better, but not completely dead, I don't think. If it comes back, I'm going to use Maracyn instead of more h2o2, because while all my fish survived, all of my plants did not. 

My anacharis, eurasian watermilfoil and hornwort (all collected locally. coincidence?) are not looking so hot. The anacharis is droopy and wilting, the milfoil is turning brown, and the hornwort is disintegrating. They're all similarly delicate/feathery, but what is surprising is that my other delicate plants (water sprite and rotala wallichii) look fine.

The tip of each plant has a relatively healthy looking spot of new growth, so hopefully I'll just lose the old leaves and not the entire plant.


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## oakleyhoma

what effect does peroxide have on animal inhabitants, other than supplying o2?


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## davemonkey

oakleyhoma said:


> what effect does peroxide have on animal inhabitants, other than supplying o2?


At 2ml/gal, I noticed no symptoms on animals when I tried this as an experiment.
At 3.5 ml/gal I noticed some stress on my snails (almost looked dead, but they pulled out of it later), but no stress on shrimp.

I stopped at that point. I know one person who dosed 4 ml/gal and lost nearly all snails. Still, there was no reported affect on other tank inhabitants.

Still, "peroxide" is not a cure, just another of many treatments to help clear out what's there after you've fixed the issue that lead to algae in the first place.


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## davemonkey

playthecello said:


> Yep, I know that. I was hoping to get it under control without using chemicals or antibiotics, but I'm not sure if that's going to be possible. A lot of the posts I've read recommend Maracyn or other form of Erythromycin to kill it, but then I saw this peroxide thread and wondered if it would work just as well, since it works as a topical antiseptic/antibiotic. It kills nasty things in paper cuts, so why not nasty things in the aquarium?


I've squirted H2O2 directly (via syringe) onto cyanobacteria. It bubbled profusly and vanished in 24 hrs.


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## playthecello

I'd say 2ml/gal dosed two consecutive days killed 90% of my BGA, along with 90% of my anacharis, hornwort and milfoil. Another day probably would have taken care of it entirely, but when I saw my plants disintegrating I panicked and stopped treatment. The plants are growing once again, but the BGA is slowly coming back too. I removed the sensitive plants last night and dosed again, and ordered some Marycin just in case. I'm tired of paying for the stupid algae-causing mistakes I made a month and a half ago and I want this stuff dead.


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## mudboots

> what effect does peroxide have on animal inhabitants, other than supplying o2?


I used better than 4ml/gal one day after using 3.??ml/gal and killed 99% of the snail population. The fish seem fine, except a couple zebra danios have nipped-looking fins, though they nip at each other regularly, so this may not have anything to do with it.



> I'd say 2ml/gal dosed two consecutive days killed 90% of my BGA, along with 90% of my anacharis, hornwort and milfoil.


I noticed pretty similar results on some of my mosses. While some pockets of them were untouched, others were nearly obliterated (using the 3.whatever and 4ml concentrations back to back).

However, I've just put in a significant order to InvertzFactory and hopefully can rely on critters to do my algae work from now on. Even though I did not many plants (yes, some did in fact perish), I lost 30-50% of my leaves (depending on species) and 100% of the leaves on my 2 red lotus. They're coming back as we speak, and now I have another baby coming up next to one of the mama plants.

H2O2 is awesome as a treatment, but overdoing it can cause more harm than good IMEO (E becaue I figure after blasting peroxide into the tank in such quantities I've killed enough plants to have formed an educated opinion). Buy some otos and other algae lovers; they're relatively cheap and make great tank additions.

P.S. - After all of this, the green water STILL did not vanish. If the conditions exist to support algae beyond the plants' capabilities, there really is no quick "cure" to your woes. Be patient, find the problem, and be patient some more...


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## wi_blue

I had green water earlier this year. I did a 3 day black out and when I saw that the water was still cloudy I put 2 willow tree cuttings (long enough to get burried in the substrate and protrude from the tank) into the tank. I was lucky enough to have cutting that already been rooted. I left them in till the water cleared.


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## The old man

I am trying the H2O2 treatment today in one tank. This tank has some string algae, BBA and a small clumb of Brush Algae.
The animals are corys, loaches, rummy nosed tetras, black line gobies, ottos, swordtails and baby mollies, one bristlenosed pleco and a lot of red shrimp. I started with one ml per gallon doses using a shringe. Will spot treat the plant leaves and driftwood each day for a week and see if I get any results. Will change about 40% water weekly. The tank gets about 5 watts per gallon of lighting 10 hrs a day and is running an Eheim canister filter. Algae did bubble a bit and some turned white today with the first treatment. No plants, fish or shrimp was effected yet. Will update this next Saturday.


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## The old man

Spent 5 hours with Microsoft upgrading to Windows 7 yesterday so I'm a day late with update.
No fish, plants or shrimp have been effected by the dosing which I increased to 2 ml after three days. Did water change today. I did cut back my lighting to about 2 watts per gallon during the treatment. Results so far: Most all the BBA has turned either red or white and the black line gobies and now the otos have been working hard on it. The string algae is almost all gone and the brush algae turned white and separated from the driftwood and I just took it out. Still got more BBA to go, but it does seem to be decreasing now. Will report back in another week. Oh yes, the blackline gobies in another tank are really working and reducing the BBA algae. This tank is not getting H2O2, but Excel overdosed instead.


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## The old man

Third week and now up to 50ml in a 29 gallon tank. All algae except for the BBA is gone. The only casualty seems to be my Vals as they have a lot of tan colored stems and quite pale looking. Will stop using the H2O2 after this week, change water and begin using dry ferts in the tank. May have to remove some of the aubias and driftwood to get the rest of the BBA with Excel. Other plants I have in the tank are Bylx Japonica, Minuta, red repens and Tennelus. I have now upped the C02 and lighting.


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## CrimsonTsavo

When my husband was taking care of my tank while I was visiting family he left the lights off (for a MONTH). After I got back and turned them back on I got a bad algae outbreak.

I used Hydrogen Peroxide and it removed all of the algae within two days. No fish were harmed. I have used this method before with the same results.

And then (the last time I had fish) I dosed my tank very-VERY heavily and killed my fish- all of them. I wasn't paying attention to what I was doing and added way too much. All of my darters were dead by the time I realized what I had done.

I have noticed the very fine leafed plants can succumb and die when exposed to peroxide. 

Other than grossly overdosing the tank I have never experienced any problems. I do not do a water change after dosing.

I also noticed no drop in the quality of my water parameters for the dead algae. (My tanks are always very heavily planted though)


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## MoonFish

freshreef said:


> thanks , what concentration did u use? i got 33% - same dosage as u mentioned?
> what about h2o2 against green water?


I have a bottle here that says 3%. I think that's what people are talking about?


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## The old man

3%


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## CrimsonTsavo

Oh yeah, what they said- it is the normal 3% strength you get at the pharmacy as a mouth wash/wound cleanser.

I can only imagine what 30+% would do. :-O


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## mudboots

CrimsonTsavo said:


> Oh yeah, what they said- it is the normal 3% strength you get at the pharmacy as a mouth wash/wound cleanser.
> 
> I can only imagine what 30+% would do. :-O


HAH!!!!! I bet that'd make for some AWESOME pearling...up to the point that the driftwood begins to turn white and everything else dissolves!


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## The old man

While I been trying the H202 dosing I was wondering about something. Has anyone ever heard or thought about if dosing with H202 could reduce or kill all the good bacteria in filters or the tank itself?


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## lildark185

Will this treatment affect mosses?


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## The old man

Did not bother mine and it cleared most all the algae in it.
I have heard it will, however hurt mosses.


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## rhodophyta

mudboots said:


> HAH!!!!! I bet that'd make for some AWESOME pearling...up to the point that the driftwood begins to turn white and everything else dissolves!


I put a couple cups of 36% in a 75 removing the fish first and leaving the filters on. It killed all of my MTS and even in tanks where I used a catalytic H2O2 doser, I am still MTS free. However with the two cups "treatment", there was a lot of foam. I had lowered the water level as low as I could to keep the filter running, about six inches, but the foam billowed up way higher than that and like in some Lampoon movie, kept rising out of the tank and onto the stand and the concrete floor. There was enough peroxide left in the foam to slightly lighten the wood stand and the concrete.


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## nfrank

i occassionally use H2O2 for spot treatment, including the filter returns. When the product comes from a new bottle, i see fizzing. However, after months of storage at room temp, it seems to loose its efficacy.
I googled shelf life of hydrogen peroxide and found a few interesting tid bits (not an exhaustive scientific study). While 3% is supposed to have long shelf life, one site mentions that "IF YOU LEFT THE BOTTLE OPEN FOR AWHILE OR HAD DIPPED A CONTAMINATED SWAB BACK INTO THE BOTTLE YOU PROBABLY RENDERED THE PEROXIDE INTO PLAIN WATER." Another site mentions "hydrogen peroxide can turn into water OVER NIGHT if you leave it open." This supports my experience. When it doesn't fizz anymore then it's not potent. Perhaps, to slow it's decomposition, it can be stored in the refrigerator. A small bottle is less than a buck, so if it is only used occassionally, get fresh stuff when needed.

I also came across an interesting advertisement that recommends 7.5 ml (1 1/2 teaspoons) of 3% or food grade H2O2 to a gallon of distilled water to make my .006% H2O2 for drinking water. This suggests its safety in low concentrations.
http://www.dancingalgae.com/hydrogenperoxide.html

However, note the term "food grade."

The most common form you buy in a drug store or supermarket is designed for (unopened) long shelf life and thus has stabilizers in it . It is not FDA approved for consumption. Some of the stabilizers are phenol, acetanilide, and phosphoric acid.

I personally will continue to use drug store H2O2 only for occassional spot treatment and not for hole tank use.


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## MoonFish

OK, read most of the thread. Dosed 3/4 cup in 75 gal. I had to convert! Don't have graduated cylinders here. I gave it a couple of glugs before but just guessing and it had little effect. I had it work a long time ago but that was by the glug method. Two days later, green hair algae turning white and the moss is fluffing up a bit rather than being tied down by the algae. Black stuff still on bolbitis but I'm not sure what that is.


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## mudboots

rhodophyta said:


> I put a couple cups of 36% in a 75 removing the fish first and leaving the filters on. It killed all of my MTS and even in tanks where I used a catalytic H2O2 doser, I am still MTS free. However with the two cups "treatment", there was a lot of foam. I had lowered the water level as low as I could to keep the filter running, about six inches, but the foam billowed up way higher than that and like in some Lampoon movie, kept rising out of the tank and onto the stand and the concrete floor. There was enough peroxide left in the foam to slightly lighten the wood stand and the concrete.


Dang Rhotophyta! I was just kidding! Thanks for taking the initiative to actually try it out at such a concentration so we can get an idea of what it'll do.


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## rhodophyta

mudboots said:


> Dang Rhotophyta! I was just kidding! Thanks for taking the initiative to actually try it out at such a concentration so we can get an idea of what it'll do.


I did this before the thread here started. I didn't leave any plants in the tank except for a few dead pieces I missed. It also killed all the MTS that even concentrated chlorine bleach would not affect. Moving the dosers around eliminated all my MTS and I have not had them back, although I do have the tiny flat snails. Those are the ones that have a spiral shell on their back but flat, not standing up like a ramshorn snail. NO idea what species they are but I've seen them in many planted tanks and on plants at pet shops.


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## Bunnie1978

Thinking about trying this on the hair algae that came with a plant I got at Petsmart months ago. I've been doing bleach dips, but I've got 12 tanks and that is ALOT of work, only for it come right back because some spore somewhere escaped me. I also move plants around quite a bit, for growout or fry tanks or whatever. 

I'm going to test on a 10 that is inhabited by tetras that I won't cry over if I kill them. 

I am going to do 3ml/gallon because there seems to be a consensus that is a safe amount?

There really aren't any other serious algae issues anywhere else in my tanks, other than black hair algae (I don't know what it's called) but that is all over.


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## Tex Gal

I've been doing 3ml per gallon in my 10g CRS tank. Doing spot treatments. Filter is off for 20 min. Then I do a 2 gal water change. Still see teeny tiny shrimp all over the place. Moss is growing better. Nothing dead.


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## ree123

I am so thankful to have found this thread. Very informative reading. I have numerous tanks and have had hair algae, blue/green algae, and the brown tuft cynobacteria algae off and on(more on) for years now. I have wiped it away, siphoned it away, and sometimes even tore down tanks and cleaned with clorox to kill it. Seems all 3 of these keep returning eventually. This has been going on for years in my fishroom. I have just figured that it is present in other tanks and by splashing and water changes and nets, I have been just recontaminating other tanks so it will never go away. I am going to try some experimenting with 3% Peroxide from the drug store shelf and see what results I can come up with. I might even tear down 1 small tank and wash it with the Peroxide and see how long it take for any algaes to return.
Thanks everyone for all the comments and I will be coming back to this thread eventually to comment again on my results.
I have 70 tanks in my fishroom so if this works it will be a blessing. My work in there is never done. ) This would make for less work for sure.
Hey, I am new to this site, but not new to the hobby, and found a thread the other day about T-shirts for this web site forum. Anyone know how I can get one or two of them ? Please p.m. me or e-mail me. Thanks ! Rick


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## Bunnie1978

Hi, Rick!! I live in Hermitage, we are close by!! You should get us some pictures of your 70 fishtanks!! That's impressive. Are you a breeder?


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## ree123

Hello Bunnie1978. I breed mostly freshwater Angels and sell to some of the LFS's. It has been a hobby for some 45 years now for me. I have some other 4 or 5 types of fish I breed some too. it is and always has been a hobby for me, but making a dollar or two every now and then is nice.
Are you aware of the local club in the process of being formed in our area at present ?


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## ree123

I also meant to say, I am still a film camera guy, but one of my teenage sons is now into the digital camera thing & I need to ask him how to take picturs and post them. I have never done that. I reckon I need to find a site on how to do that to learn. I am so computer illeterate. LOL


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## ree123

Bunnie1978,
Know how I can get a, or some, T-shirts from this forum that I found the other day on another thread ? If so, your direction would be appreciated.
Thanks, Rick


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## Francis Xavier

h202 will kill algae if you spot dose it with a syringe - you'll know it's taking effect because the algae will fizz and bubble, and you should start see plants pearling fairly quickly, since the extra oxygen molecule causes the water to be supersaturated with oxygen.

However, it does have the effect of hurting the plants - it is toxic to them. But using an appropriate dose (a couple mL or so) in an area will kill the algae for you to remove, and send the plants into a melting state (well, I've only done this with HC, so your mileage may vary), but a side effect of this melting is that at least with HC the plant nodes will grow back even -smaller- than they were before, which is excellent for say the appearance of a carpet in a Nano aquarium. I have dosed h202 to do this to HC in my tanks on purpose even when no visible algae is present just to force HC to grow in smaller.


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## catweazle

I wrote something about it on my site.

The following link is the google translation from Dutch to English. This means it is broken english, but these are my experiences. Feel free to shoot at it, if you want to read it.

My thoughts


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## Aquaticz

I used H202in two tanks that previously had no C02. Once I added the C02 I wanted to globally treat BBA. I used 2 ml per gallon & it made a huge dent in the BBA, to the point where now of having stable CO2 levels...bye ..bye..BBA


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## f1ea

catweazle said:


> I wrote something about it on my site.
> 
> The following link is the google translation from Dutch to English. This means it is broken english, but these are my experiences. Feel free to shoot at it, if you want to read it.


Thanks for the link. I read you doc and according to the table you provide, the LC50 (concentration that kills 50% of a given species) of the simplest "animal form" on the list (the mussel) was 5ppm. The LC50 for snails is about 18 ppm. (100% H2O2)

So, for the usual 3% H2O2 solution, i used your calculator for:

1) The absolutely animal safe concentration (target 5ppm)
>> 6 ml per 10 Gal (about 0.6 ml per Gal)

2) The snail safe concentration (target 18 ppm)
>> 22 ml per 10 Gal (about 2.2 ml per Gal)

3) Deadly for algae specimens (target 2.5 ppm)
>> 3 ml per 10 Gal (about 0.3 ml per Gal)

Aquatic plants seem to start getting damage at 34 ppm.

i've read here that many people have dosed up to 2ml/gal, which is about the snail safe concentration... Very consistent with Davemonkey's experience a few pages back. Interesting.

EDIT: Oh, the LC50 for BGA (cyanobacteria) is with a 48hr exposure. And H2O2 has a hlaf-life of 8hrs... 
so exposing BGA at 5ppm, for 48 hrs should kill 50% of your BGA. Regular algae had an LC50 with a 72 hrs exposure...

Again, very interesting. Anyone willing to experiment?


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## catweazle

My first reaction is keep away from it. Do not use any chemicals. But if you want to use it, gather information. I did read some MSDS. For your convenience here are some URL's, some I mentioned did not exist anymore, but I found some others. I'm always interested in more MSDS's, because it it gives me the capability to expand the table.

Look at the different ecotoxicolological info:

http://msds.fmc.com/msds/100000010225-MSDS_US-E.pdf
http://purehealthsystems.com/h2o2-msds.html
http://www.oltchim.ro/en/uploaded/H2O2_rev6_eng.pdf
http://www.scholarchemistry.com/msds/Hydro_Perox_3pct.pdf
http://agrowingalternative.com/msds.htm

@f1ea,
The LC50 for the mussel (Dreissena polymorpha) is 5ppm during 56 hour. You'll have to take the time in acount, indeed. Algea (without any specs given) has a *I*C50, 72 hour, 2.5 ppm. The halftime varies from 8 hours to 20 days, but you can asume that in a aquatic environment it won't last 20 days.

By the way, I think a Gal is 3.8 liter. Is that true?


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## f1ea

catweazle said:


> My first reaction is keep away from it. Do not use any chemicals. But if you want to use it, gather information. I did read some MSDS. For your convenience here are some URL's, some I mentioned did not exist anymore, but I found some others. I'm always interested in more MSDS's, because it it gives me the capability to expand the table.
> 
> Look at the different ecotoxicolological info:
> 
> http://msds.fmc.com/msds/100000010225-MSDS_US-E.pdf
> http://purehealthsystems.com/h2o2-msds.html
> http://www.oltchim.ro/en/uploaded/H2O2_rev6_eng.pdf
> http://www.scholarchemistry.com/msds/Hydro_Perox_3pct.pdf
> http://agrowingalternative.com/msds.htm
> 
> @f1ea,
> The LC50 for the mussel (Dreissena polymorpha) is 5ppm during 56 hour. You'll have to take the time in acount, indeed. Algea (without any specs given) has a *I*C50, 72 hour, 2.5 ppm. The halftime varies from 8 hours to 20 days, but you can asume that in a aquatic environment it won't last 20 days.
> 
> By the way, I think a Gal is 3.8 liter. Is that true?


Yes, 1 US Gal = 3.78 liter

And thanks for the correction, the Algae IC50 (inhibitory) is 2.5 ppm @ 72 hr. 
BGA has IC94 of 1.7 ppm @ 48 hr.

There's a LOT of great information in your paper, and it was very well written. Thanks for sharing it.
I wanted to summarize some starting/threshold values as a starting guide...


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## catweazle

A lot of it is based on English documents. I just put it all together. Still I have to rewrite it. The focus must be to grow plants and not destroying algea. It is all about balance (even EI I would call a balance), and a aquarium is a complex thing. H2O2 is not the answer. It could help, but it is not an answer. 

But let me make you laugh. I spent about one hour on your calculations because I thought they were not correct. I saw 10Gal, and somewhere I thougth 380l. Took me some time to do 10*3.8=38. Rather stupid.


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## almightydolla

Inspired by this thread I tried a few experiments in my tanks with h2o2, here's what I found:

tank 1 (5gal nano). I dosed 3ml/gal daily for 4 days. i just dumped it in, no lights off and left the filter running. Clado and hair algae in areas with good water flow melted. Algae deep in the moss was not affected. No noticeable affect on plants (rotala, marseila, blyxa and sygnonanthus and assorted mosses). Riccia melted by day 2. The lone otto cat's underside of his gills turned pretty bright red, but it's behavior did not change. He's back to normal now. Shrimp (RCS and Amano's) seemed fine. The only snails in that tank were those tiny flat spiral shelled ones, whatever they are. There seems to be more of them now.

tank 2 (60gal 4.5wpg co2). Dumped in daily again. With more risky stuff in this one, I decided to try the recommended 2ml/gal approach, and dosed for 4 days. Clado and hair algae in areas with good water flow turned slightly brown and eventually died off. BBA shrugged it's shoulders and carried on. No plants affected (blyxa, copious syngonanthus, tonina, rotala, crypts, swords and mosses). No fish (pygmy corydoras, otto's) or shrimp (RCS, Amano's) seemed affected. Lost a bunch of MTS, but pond snails, ramshorn and those tiny flat shelled ones did not seem very affected.

After the 4 days, I manually removed as much dying algae as I could. The hair algae is completely gone from both tanks, but the clado still resides deep in the moss but has not attempted any sort of comeback. The Amano's quickly take care of any that does crop up.

Tanks 3, 4 & 5 (24, 24 and 12gal) were dosed with a single shot of 2ml/gal starting on day 4. All algae's did not seem affected in the slightest by the single dose. They continue to grow in a mockingly fashion.


h2o2 loses it's potency pretty quick. I could see the difference over the course of 4 days in terms of o2 bubbles produced. If you don't use it up quick once you start opening the bottle, it's strength diminishes. My results might have varied on the single shot if I used it immediately after opening up the bottle.


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## art_b

Will 2 ml/gallon treatment affect fine leaf plants like ambulia (Limnophila sessiliflora). I have lots of ambulia on my tank (and hair algae).


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