Skip to content
View in the app

A better way to browse. Learn more.

Shrimp Keepers Forum

A full-screen app on your home screen with push notifications, badges and more.

To install this app on iOS and iPadOS
  1. Tap the Share icon in Safari
  2. Scroll the menu and tap Add to Home Screen.
  3. Tap Add in the top-right corner.
To install this app on Android
  1. Tap the 3-dot menu (⋮) in the top-right corner of the browser.
  2. Tap Add to Home screen or Install app.
  3. Confirm by tapping Install.

A guide to spot dosing with H2O2 (Hydrogen Peroxide)

Featured Replies

A Generally accepted method of spot dosing with H2O2 (Hydrogen Peroxide)

We will work with a 30cm cube to make all calculations easier (30L of water) and be using 3% solution of H2O2

Remember you are playing with a chemical that oxidizes when it comes in contact with organic matter, so always use as little as possible as overdoses can damage your invertebrates (shrimp) or nitrifying bacteria causing your tank to cycle again.

“MAXIMUM†dosage in a 30L body of water is 15ml in a 48 hour period, this will increase total peroxide levels by 15 mg/l, generally this is deemed safe, but always best to work well and truly under this level.

Things you will need:

Half hour of time

Hydrogen Peroxide (3% solution) - easily purchased from your local super market or pharmacy

1x 10ml syringe – these are available relatively cheaply from your pharmacy

post-963-139909847026_thumb.jpg

Prepare your tools:

Draw up 5ml of your H2O2....

If this is the first time you’re doing this, before you start the actual dosing process add 2.5ml of tank water as this will give you slightly more ammo to play with without increasing your overall dose.

Prepare your tank:

Turn off all filters and pumps.

This is so you don't have a current in the body of water (should only take 30seconds to settle). also if your dosing near your intake best to avoid getting H2O2 in the filters as it will go bananas on all the good bacteria you have in there.

Plan your attack:

Take a step back look at what your treating and figure out if you have more than one place to dose or if its just localized less time your filters are off the better.

Not an Ideal situation to be fiddling around for an hour with your filtration off

Attack:

Dose sparingly directly above the site you wish to treat, within a second or two you will see it bubbling away. try to avoid sensitive mosses and such if in doubt patch test first.

An example of what the effect is:

https://www.youtube.com/watch?v=39KRTN-IVJw

Finish up:

Wait a couple of minutes and turn everything back on.

It is generally suggested to do a water change (one third) if you wish to re-dose within 48hrs, but as we are only playing with a third of the maximum dosage you can repeat this the next day if you feel it necessary, or if you have more algae than this dosage allows you to treat.....

Good Luck and if in doubt ask questions on the forum, there is plenty of experienced shrimp keepers that are willing to help out!!!

post-522-139909857929_thumb.jpg

  • HOF Member

Sorry guys, started a clean thread in the appropriate section for this. Deleting 2 posts killed the other thread for some reason :sorrow:

I remember my question.

Does H2O2 kill all algae and cyanobacteria (i.e. blue-green algae)?

  • Author

Lol shorter answer than last time, but yes lol

  • Author

Well it helps gets rid of it, blue green is usually always in the tank just not in its slimy form. Oxygen "KILLS" it :)

If you want to get rid of it, dose h2o2 on it but the spot its growing in is probably a dead spot of flow, and or oxygen.

Make sure you have enough flow, more oxygen in the tank and you shouldn't have a repeat of the outbreak.

Manual removal will only stimulate it to grow harder and faster. Especially if you haven't addressed the original cause. :)

  • HOF Member

That's the same stuff I get from my Coles for spot dosing too. I ran out so I diluted some of the concentrated stuff that I have for my Sochting. Accidentally overdosed and caused my tank to cycle again. My cherries came through fine but lost all my DAS. :mad:

  • Author

Lol I took that photo in Coles.

  • HOF Member

LOL. Also, here is what happens to moss if your H2O2 mix isn't right:

8188103747_c68e3330e1_c.jpg

It's coming back to life slowly though.

  • Author

Wow, looks like the after effect of Hiroshima lol....

50%?

  • HOF Member

I think it was around 10%. I had some stubborn hairlike algae taking over.

  • Author

Well you certainly showed it who was boss lol.

I found you can pretty much apply 6% on just about anything. Haven't been game enough to go more than that.

I would have thought 10 wouldn't have been too bad though as long as u don't let it sit too long.

  • 1 month later...

I'm 100% new to this idea but I did once have that horrid green hair-like algae take over my java moss and I had to rip most of it out to get rid of it. What I'm wondering is will it work fine on the annoying stuff that grows on the glass (browny green alga, yep I haven't looked it up yet but my little tank is starting to get scratched) and are you able to use a needle with H202 for more precise dosing?

  • Author

Hmmm not sure about glass as it wouldn't have time to sit but maybe a few applications over the space of a week would help. Problem is you would still have to scrape off the dead algae...

What do you use to clean the glass that's causing scratches? When it comes to the brown stuff usually a magnet cleaner works rather effective, without scratching the glass.

As for needle yes you could add that but bare in mind that whilst you may be able to apply it to a more precise area, unfortunately when you release it, the natural tendency for the fluid to mix with water will equal a broad spreading anyway. Don't be too concerned with this as you are using a really diluted amount. I have tested this on some really touchy plants and at least double this dosage with no ill effect :)

I do have a standard plastic scrubber on a stick as you get from aquarium stores but it gets a bit hard due to it's huge size in a little tank. I have used the back of a normal sink sponge (green scrubby part that is plastic) and have scratched before which surprised me as I wasn't doing it hard and it's just a rough plastic coating which gets used on normal glasses and not leave a mark.

  • 10 months later...

Just want to clarify that if im dosing a tank thats 120litres i can safely dose 20ml without harming shrimp?

Presume you're using 6% H202, then 20ml is OK, BUT ensure you either turn off your filter, or introduce it away from you filter inlet..

Thanks BB im treating bba on my mesh dividers so its well away from the ilter inlet and i will turn off the filter. So i buy 6% not 3%?

I use 50%... Bhahahahahahahaha..but 6% is the way to go ! Just slow, gentle and spot dose :-)

Cool thanks

Do i need to water change if im not redosing next day?

Doubt it's necessary, but if you're unsure, and as a precaution, perhaps it wouldn't hurt. check/keep an eye on your nitrate level (overdosing of H02 will kill the good bacteria in your filter).

Thanks BB

im excited to rid my bba but im crapping my pants with te process lol

Fingers crossed it all goes well!

I would remove your shrimp as a precaution

i have wiped out a whole tank full of shrimp In the past dosing with H2o2

I would remove your shrimp as a precaution

i have wiped out a whole tank full of shrimp In the past dosing with H2o2

Or remove what you are trying to treat. And treat it outside the tank. It would be easier than trying to catch shrimps.

Can't your mesh divider be removed?

Replace it with something else as a temporary divider, or a spare mesh divider. Always good practice to have spares.

You can then treat the item outside of your tank and dose higher levels to your heart's content.

I cant remove my shrimp as i dont have another tank to put them in =[

Did the tank get wiped out due to the amount dosed?

My dividers are siliconed in and not removeable either.

hrmmm what to do?

Looks like you will have to weigh up the risks of dosing in tank or breaking the silicon and removing the mesh to treat outside the tank.

I'd be going with the 2nd option.

Silicon can always be replaced.

The cleaned mesh can be pushed 1cm into the substrate, and you lower the water level of the tank to re-silicon the top of the mesh after the water line has dropped to hold it in place. So the bottom is held in place by the substrate, and you apply new silicon at the top to hold the top part of the mesh.

Create an account or sign in to comment

Account

Navigation

Search

Search

Configure browser push notifications

Chrome (Android)
  1. Tap the lock icon next to the address bar.
  2. Tap Permissions → Notifications.
  3. Adjust your preference.
Chrome (Desktop)
  1. Click the padlock icon in the address bar.
  2. Select Site settings.
  3. Find Notifications and adjust your preference.