Jump to content

Hydrogen peroxide and beneficial bacteria

Recommended Posts

Hi folks,

So I've been letting my Val, crypts and dwarf sag grow wild as I'll soon be adding the new tanks and why buy more plants when I can grow my own 🙂

The only thing is I do have a bit of BBA in the tank which is being managed by the inhabitants but never really goes away. I'm considering giving the plants a quick HP dip before they move but I was also hoping to transfer as much beneficial bacteria as fish will be moving at the same time.

I've got cycled sponges for the new tanks but as we know the plants will be loaded with it as well and I was wondering if it's possible to kill algae without decimating the bacteria?

  • Like 1
Link to comment
Share on other sites

I think the best bet would be the reverse respiration method (see pinned thread on the topic)

Anything that chemically kills algae is going to kill the bacteria especially HP as that is used as an antiseptic to clean wounds and to teach children the importance of not falling over. (It stings like crazy)

  • Like 2
Link to comment
Share on other sites

Thanks @Flumpweesel I remember seeing the post before but I'm the wrong side of 50 and forget lol

It's very useful and informative, however would it not have the same affect as HP on bacteria as algae with both being aerobic?

Now you've reminded me it will most likely be the way to go for me and I guess I'll just have to cycle more sponges if the bacteria does indeed die off.

My back up plan is to utilize my guppy grass farm also known as my shrimp tank, I throw hand fulls of the stuff away weekly so I'll just toss it in the new tanks as ammonia sponges 🙂

  • Like 1
Link to comment
Share on other sites

You’re all correct, seltzer will kill much or all of the BB. However, there may be two options for you.

RR’s algicidal effects were first observed by @Guppysnail and are actually due to the pH shift, with the oxygen or CO2 levels having little to do with it. RR was initially designed to asphyxiate the pests, and seltzer, having no oxygen content or residue and costing just pennies, it just seemed like an obvious choice to me.

But it was the shift from a pH of only 3 in seltzer to the sudden shift to normal water pH (my water has a pH of 😎 that destroyed the enzymes in the algae. That was about a shift of pH3 to pH8 or a total pH shift of 5.

The problem is there’s no oxygen in seltzer, so the BB is also killed. Seltzer being highly acidic followed by relatively alkaline plain water, caused the pH shift direction needed to dissolve the algae cell contents.

But the pH shift can be done in the opposite direction. If done in the opposite direction, not acid to alkaline, but alkaline to (more acidic) normal water, it should also kill the algae. Except it precipitates the algae cell content rather than dissolving it.

This can be done by soaking the plants in ‘alkaline water’ instead of seltzer. You see many brands of this stuff in supermarkets marketed as health drinks. But the difference being, alkaline water has tons of oxygen in it. In fact, some of them are oxygen infused. The brand called ‘Oxigen’ has so much oxygen in it it’s considered “Oxygen Soda”.

Smart Water is probably the most well-known but all of them have a pH of 9-12, (brand dependent). It’s entirely possible that you could soak everything in Smart Water or the like for the same time periods as RR and when it’s returned it to regular water, it’s almost as strong a shift in pH as seen in RR but reversed. I’ve seen alkaline waters in the supermarket with a pH of 12. Upon return to normal water, let’s say a pH=8, that’s a shift of 4. Pretty severe. This may also destroy the algae. This direction is the actual method they use to precipitate algae for those thick, green health drinks.

So, the RR direction dissolved the enzymes, but the opposite direction precipitates them. Either way, the algae should not appreciate it!  It should work but I need to stress, it’s entirely theoretical.

I should also note that total darkness is even more important here than in RR. It will keep the stomata closed and help protect the plants from the external solution.

The BB however are in friendly territory in alkalinity. It should not negatively affect them. The actual chemical reactions of the BB consuming ammonia and nitrite take place at pH13 and pH9 in highly localized environments (just microns in area) respectively. 

I tried to add this link below but unfortunately, you’d need a subscription to read it. However, here’s an excerpt from a study done at the Institute of Water and Environmental Engineering, Polytechnic University of Valencia, Spain:

NOB (nitrite oxidizing bacteria) were strongly affected by low pH values (no activity was detected at pH 6.5) but no inhibition was observed at high pH values (activity was nearly the same for the pH range 7.5–9.95). A kinetic expression for nitrite oxidation process including switch functions to model the effect of TNO2 (total nitrite) concentration and pH inhibition is proposed. Substrate half saturation constant and pH inhibition constants have been obtained.”

I’m not one for speculation so please take this as such. I’ve never tested this, but their numbers do add up.


Yet there’s another, mechanical approach that also may work. In a sense, I’ve tested this one, not on algae, but on snails and their eggs. But in theory (again), the physical size of algae cells and snail eggs is much closer than either of them is to bacteria.

During the many months of designing RR, I somehow contaminated two Fluval FX6’s with very, very tiny, black snails (poppy seed size, I don’t know what they were). The media (Matrix) was full of hundreds of them. I thought I was careful, but I screwed up somewhere.


I asked @Odd Duck about it and she had experience with this in that she noted ultrasound is excellent for demineralization of parts but is very inefficient in killing bacteria. When she told me of this, I sonicated that media for 30 minutes. It killed all of the snails and seemed to have no effect on the BB or rather I should say, the biofilters worked just as well before and afterwards.

Sonication efficiency is based on the size of the target. It produces bubbles the size of the ultrasound waves themselves that explode. But the bubbles it produces are too large to kill many bacteria and simply bypasses most of it as @Odd Duck noted. Sort of like a small object floating over a large ocean wave whereas a larger object sees the wave violently crash into it.

Sonication is much closer in size for snails, algae cells and larger entities. To that end, it has been very successfully used as an algicide. My first non-chemical plant sterilization design that @OnlyGenusCaps and I had discussed prior to embarking on RR was ultrasound. I used data from several extensive studies done on this during this early design of RR, but this company has a concise, non-technical description of the process and its extraordinary success rates (although this particular one is about huge, industrial volumes of water but it’s the same concepts):

Algae Control for Lakes & Reservoirs | Chemical-Free - LG Sonic

For a small tank or to treat media or sponges, this drop-in sonicator is inexpensive and is what I used to rid my filter media of snails without harming the BB:

Portable Household Ultrasonic Cleaner-Mini Immersible Ultrasonic Cleaning

Despite their marketing rhetoric as a disinfectant, it had no effect on my BB as far as I can tell as @Odd Duck predicted. It will however drive virtually every last bit of schumtz out of your sponges and if the theory is correct, it should even kill the algae. This 50-watt device has enough power to sonicate a maximum volume of 2 gallons of water.

Sonicator’s are more efficient as the water volume increases. This is why a jewelry cleaner needs 20 watts for just a pint of water whereas a 50 watt has the same effect on a gallon or 2. IMO, I’d try to keep it no larger than 1 gallon or use a higher wattage sonicator if you need more space.

As a rule, I don’t feel comfortable posting anything I have no empirical or mathematical proofs for so please accept this as entirely theoretical. But it seems to have good odds for success should you wish to experiment with it. Good luck.



























  • Like 1
  • Love 2
Link to comment
Share on other sites

Just as an FYI, I’ve been known to lay sponge filters on their side in a shallow dish of straight peroxide to treat the outside for BBA.  The goal being to treat the BBA without completely decimating the the beneficials deeper in the sponge.  I will roll it in the dish, even stand it on its head (I’ve usually removed the sponge from the core structure) to expose the BBA but I try not to fully saturate the sponge.  I also would NOT treat all the biofiltration at once this way.  I’m a big believer in backups to my backups so I always have loads of biofiltration that isn’t getting treated.

That being said, I’ve got a little sonic jewelry cleaner and plenty of BBA to experiment with.  I might have to plop some BBA tufts in there and give it a buzz!

Edited by Odd Duck
  • Like 2
Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

  • Create New...