# Is it possible to eliminate algae by sterilization



## tiger15 (13 May 2022)

Algae has to start somewhere, via spores or baby algae hitchike with contaminated water, plants or fish.  If I can sterilize water with algaecide and don’t introduce new contamination, is it possible to eliminate algae permanenty.


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## erwin123 (13 May 2022)

tiger15 said:


> Algae has to start somewhere, via spores or baby algae hitchike with contaminated water, plants or fish.  If I can sterilize water with algaecide and don’t introduce new contamination, is it possible to eliminate algae permanenty.


its easy to do an experiment, fill several test tubes with water from your tank, "sterilise" it with different brands of algaecide. leave the test tubes somewhere where they get a reasonable amount of heat (if in a cold climate), and monitor to see if algae appears in the test tube after a few weeks.


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## Hanuman (13 May 2022)

tiger15 said:


> Algae has to start somewhere, via spores or baby algae hitchike with contaminated water, plants or fish.  If I can sterilize water with algaecide and don’t introduce new contamination, is it possible to eliminate algae permanenty.


Short answer is no. Not possible. Unless you are in a sterile lab environment with very strict protocols in place, it is virtually impossible. Algae spores and bacteria (like BGA) can be airborn, so you can clean, brush, burn and sterilize all you want but algae will come back eventually, and faster than you think.


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## tiger15 (13 May 2022)

erwin123 said:


> its easy to do an experiment, fill several test tubes with water from your tank, "sterilise" it with different brands of algaecide. leave the test tubes somewhere where they get a reasonable amount of heat (if in a cold climate), and monitor to see if algae appears in the test tube after a few weeks.


Actually Donnie Wong had conducted an experiment comparing a bottle of tap water versus aquarium dosed tap water exposed to sunlight.  As expected, contaminated tap water turned green quickly, but not pure tap water.



Hanuman said:


> Short answer is no. Not possible. Unless you are in a sterile lab environment with very strict protocols in place, it is virtually impossible. Algae spores and bacteria (like BGA) can be airborn, so you can clean, brush, burn and sterilize all you want but algae will come back eventually, and faster than you think.


Yes, airborne algae spores such as BGA cannot be prevented, but water born algae theoretically can be.  Note that algaecide cannot sterilize 100% algae species without also killing plants, BB and fish with some recalcitrant algae stick  around.  But if it can eliminate some stubborn algae such as bba or thread algae, it’s an accomplishment.


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## Hanuman (13 May 2022)

tiger15 said:


> Actually Donnie Wong had conducted an experiment comparing a bottle of tap water versus aquarium dosed tap water exposed to sunlight. As expected, contaminated tap water turned green quickly, but not pure tap water.


Tap water is somewhat filtered and treated with chlorine and/or chloramine. Consequently, pathogen and spore load are reduced. I am pretty confident if he was to leave that little experiment run for over a month he would slowly see algae develop in the tap water bottle. In fact he could run the same experiment with some brand name water bottle (basically RO water) that the end result would be the same, assuming of course that bottle is uncapped. The rate at which algae develops would probably be slower due to the poor mineral content.


tiger15 said:


> Yes, airborne algae spores such as BGA cannot be prevented, but water born algae theoretically can be. Note that algaecide cannot sterilize 100% algae species without also killing plants, BB and fish with some recalcitrant algae stick around. But if it can eliminate some stubborn algae such as bba or thread algae, it’s an accomplishment


BGA is a bacteria despite its name, but many algae spores are also airborn. Not being an algae expert I can't say which are airbone and which are not, but to me it is virtually impossible to eliminate even the only-waterborn algae spores because it would require an extreme level of sterility which cannot be carried out in our homes/tanks. Spores can survive extreme conditions and still be viable for future reproduction. My opinion on this is that going down the path of sterilization is in fact a bad approach because all these algae can be controlled without eradicating them if you are properly taking care of your tank. The idea of wanting to eradicate something usually finds its roots in the fact that we don't understand how things work and because we believe they are a thread to us. Not that algae are a threat, but certainly become an annoyance if we let them proliferate due to a lack of understanding.


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## Simon Cole (13 May 2022)

tiger15 said:


> Note that algaecide cannot sterilize 100% algae species without also killing plants


Based upon the idea that they all share the same genetic ancestor. The thing is, we share many genes with lettuce*,* but that doesn’t make us part salad. You would need to convince me that all algaecides are non-selective. 


Hanuman said:


> Not being an algae expert I can't say which are airbone and which are not


Water droplets are airborne. A coconut is also airborne in a hurricane. I am guessing spore mass is a bit lighter that both, so perhaps around 30 ng.


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## Hanuman (13 May 2022)

Simon Cole said:


> Water droplets are airborne. A coconut is also airborne in a hurricane. I am guessing spore mass is a bit lighter that both, so perhaps around 30 ng.


A massive cumulonimbus cloud is also airborn. The idea being not transported by water molecules I suppose?


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## seedoubleyou (13 May 2022)

As already aluded to, no.
A Steriliser by virtue does what it was named to do. It sterilises the cells within the algae to stop them spreading, and to be most effective you’d require the right UV and flow rate.
A Steriliser is merely an additional tool in combatting nuisance algae, you need to be manually removing it too, and shifting things within your tanks parameters to give the plants the upper hand.
ie. Lighting schedule, co2, fertiliser, water changes, deadspots, flow, detritus build up etc…..


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## tiger15 (13 May 2022)

Simon Cole said:


> Based upon the idea that they all share the same genetic ancestor. The thing is, we share many genes with lettuce*,* but that doesn’t make us part salad. You would need to convince me that all algaecides are non-selective.
> 
> Water droplets are airborne. A coconut is also airborne in a hurricane. I am guessing spore mass is a bit lighter that both, so perhaps around 30 ng.


Humidity in indoor environment is in vapor form, not water droplets as in rainstorms, so it it not capable of transporting algae spores from one water body to another.  Outdoor windstorm is different and can seed new water bodies with algae, plants, and even fish and crustaceous.  This is why swimming pools and outdoor water fountains need to be chlorinated to prevent algae and bio growth.  

Many algaecides are selective such as Glutaldehyde and API Agaefix.  Glut is  effective against BBA, but not Clado, green thread algae, green water, BGA, GSA and GDA.  Agaefix is effective against Clado, green water, and green thread algae, but not BBA , GSA and GDA.  Chlorine is broad spectrum that can kill all algaes  but also  fish and plants so it is off limit to aquarists.

If one can find a broad spectrum algaecide that is safe for fish and plants, shouldn't it be effective against all algaes. Note that biocides and algaecides must be applied periodically  or else their effect will go away.


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## jaypeecee (3 Jun 2022)

Hanuman said:


> BGA is a bacteria despite its name, but many algae spores are also airborn. Not being an algae expert I can't say which are airbone and which are not, but to me it is virtually impossible to eliminate even the only-waterborn algae spores because it would require an extreme level of sterility which cannot be carried out in our homes/tanks.


Hi @Hanuman 

Use of a UV-C sterilizer should kill any _*waterborne*_ algae and cyanobacteria. No chemicals needed. I've used UV-C sterilization to good effect several times. Just need to ensure that the dwell time is optimized.

JPC


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## seedoubleyou (3 Jun 2022)

In a word, no.
UV sterilisation will not eliminate algae. It sterilised the cells to prevent reproduction. You would be required to manually remove the algae also, or use other methods to help eradicate it.


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## tiger15 (3 Jun 2022)

seedoubleyou said:


> In a word, no.
> UV sterilisation will not eliminate algae. It sterilised the cells to prevent reproduction. You would be required to manually remove the algae also, or use other methods to help eradicate it.


When I said sterilization, I don’t mean by limiting it to UV alone but also chemical sterilization.  UV can sterilize only free floating algae and spores, but not attached algae.  If you can root out attached, free algae and spores by chemical and physically means,  I don’t see why you cannot eradicate certain algae as algae don’t start spontaneously and must be seeded.  That said, some algae spores are air born, hitchhiked with  new plants, fish or tap water, or contaminated on glass lids and  equipment waiting to be seeded.  If you dose algaecide on regular basis and prophylactically, I don’t see why you cant  eradicate certain algae, but never all algae.    There is no broad spectrum algaecide that can eradicate all algae without also killing live stock and plants, for example, chlorination.  Glutaraldehide is effective against BBA but not Clado, and AlgaeFix is effective against Clado but not BBA, and neither is effective against GSA.  So the premise of eradicating all algae by sterilization is not possible, but eradicating some algae is possible.


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## FrankR (3 Jun 2022)

What about Hydrogen Peroxide?
The saltwater lunatics dose their tanks with H2O2  or use oxydators to keep algae at bay.


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## JoshP12 (3 Jun 2022)

Simon Cole said:


> Based upon the idea that they all share the same genetic ancestor. The thing is, we share many genes with lettuce*,* but that doesn’t make us part salad. You would need to convince me that all algaecides are non-selective.


I ate my ancestor for dinner 😳.


Simon Cole said:


> Water droplets are airborne. A coconut is also airborne in a hurricane. I am guessing spore mass is a bit lighter that both, so perhaps around 30 ng.


Sheesh and we thought the lean dosing thread was comedic - that cracked me up … like the coconut 😂.


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## seedoubleyou (4 Jun 2022)

FrankR said:


> What about Hydrogen Peroxide?
> The saltwater lunatics dose their tanks with H2O2  or use oxydators to keep algae at bay.


Do they?
Edit: decided to Google it as I should of initially. I kept reed tanks and always dipped frags in H2O2 before going into the tank, to remove excess algae. 
I never realised it could be dosed into the tank either.
I never had algae issues, other than a severe outbreak of bryopsis once. I killed that off with Flucanazole, and never had an algae issue ever again.


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## seedoubleyou (4 Jun 2022)

tiger15 said:


> When I said sterilization, I don’t mean by limiting it to UV alone but also chemical sterilization.  UV can sterilize only free floating algae and spores, but not attached algae.  If you can root out attached, free algae and spores by chemical and physically means,  I don’t see why you cannot eradicate certain algae as algae don’t start spontaneously and must be seeded.  That said, some algae spores are air born, hitchhiked with  new plants, fish or tap water, or contaminated on glass lids and  equipment waiting to be seeded.  If you dose algaecide on regular basis and prophylactically, I don’t see why you cant  eradicate certain algae, but never all algae.    There is no broad spectrum algaecide that can eradicate all algae without also killing live stock and plants, for example, chlorination.  Glutaraldehide is effective against BBA but not Clado, and AlgaeFix is effective against Clado but not BBA, and neither is effective against GSA.  So the premise of eradicating all algae by sterilization is not possible, but eradicating some algae is possible.


Ah my mistake. Do chemicals actually sterilise cells  like Ultra Violet light does?


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## zozo (4 Jun 2022)

I'm not a fan of any chemical treatments against whatever... I rather use elbow grease... But "The one-two punch tut at the planted tank.net"
Is about applying Glut and Peroxide in 2 short bursts over a short period. And it seems people that did it report it works very good against algae.








						The "One-Two Punch" Whole Tank Algae Treatment
					

NOTE:  Others have reported deaths of shrimp, snails, and fish - particularly known sensitive ones.  Please read the entire thread for details before experimenting.  For anyone who wishes to try this, I am changing my initial recommendation for H2O2 to 2 tbsp. per 10G, down from 4 tbsp.  This...




					www.plantedtank.net
				




I never tried it... Use at your own risk...


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## Hanuman (4 Jun 2022)

Yes both chemical and the method works just fine. I have used that method but there is something that one should do after such a treatment is do multiple WCs perhaps even three during the week because the amount of organics generated by such a treatment will most likely re-initiate a new algae outbreaks. The amount of WCs will depend on how much algae there is. Something to note with that method is that if you have, Valisneria, Rotala Ramosior 'Florida' or other Rotala in fact, Najas sp. Roraima etc etc that treatment will most likely kill the plants or at least strongly damage them, so removing those plants (if possible) prior the treatment is a must. I've been in that position so I know for a fact those plants do not like those treatments.


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## zozo (4 Jun 2022)

Most if not all truly aquatic plants will not take chemicals like glut and peroxide very well their tissue is too soft and gets damaged... Potamogeton sp. is also one of them.


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## tiger15 (4 Jun 2022)

zozo said:


> I'm not a fan of any chemical treatments against whatever... I rather use elbow grease... But "The one-two punch tut at the planted tank.net"
> Is about applying Glut and Peroxide in 2 short bursts over a short period. And it seems people that did it report it works very good against algae.
> 
> 
> ...


I have been dosing Glut and spot treating with peroxide prophylactically for years.  Based a toxicity data and personal experience, Glut has low toxicity that dosing as much as 5X as recommended by SeaChem will not harm life stock.  I only spot spray with 3%  peroxide on exposed plants and hard surfaces when I drain down the tank during weekly water change.  I don't recommend dosing peroxide because it is hard to control the effective concentration as peroxide is volatile and light sensitive.  That said, I am indirectly dosing peroxide when I refill the tank as sprayed peroxide will fall off, but unlikely to reach toxic levels to life stock.   

I don't think there is anything wrong dosing chemicals  prophylactically to aquatic garden as homeowners regularly dose herbicides to their lawn.  Even though Tom Barr and Dennis Wong preach fixing the fundamentals to stop algae, they both recommend using algaecides as the last resort.  Dennis is marketing his own brand of repackaged Glut and  Barr has many discussions on  various algaecides.  I am sure Barr,  Wong and many aquarists use algaecide more often than they admit.


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## zozo (4 Jun 2022)

tiger15 said:


> many aquarists use algaecide more often than they admit.


Might be, especially when it concerns showpieces when you need to be in top-notch condition on a specific date. I'm not saying it's cheating either...
I'm just not a fan and don't mind a few algae in my tanks and my tanks are only for me the show, all that visit my place now and then don't see the difference between algae and plants and rarely look longer than 20 seconds to the aquariums.

Tho me too as many others experimented with glut and peroxide in the past and it works... Regarding glut, some plants hate it others thrive on it that will not grow in low energy otherwise.  Personally, I'm just sitting on my pennies and I see no value added to spending money on plants and glut if I can also grow plants that don't need it. Plants are plants I find them all equally beautiful and equally fun to grow in their own right.  Thus for me the question mark about why should I is bigger than why should I not use chemicals for fun. I once did have my share of fun with both and like it without better and less hassle, rather lazy than tired running from one bottle to the other so to say... 

So for me not being a fan is more of an opinion and not at all judgemental.


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## John q (4 Jun 2022)

tiger15 said:


> Glut has low toxicity that dosing as much as 5X as recommended by SeaChem will not harm life stock


I beg to differ. Glutaraldehyde kills fish, anybody dosing 5x  standard dose is playing Russian roulette with there livestock.
Maybe a close up photo of fish subjected to 5ppm~ 10ppm long term of glutaraldehyde will sway my judgment, I suspect we won't get photos.


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## Tim Harrison (4 Jun 2022)

Isn't it better to concentrate on growing healthy plants than eradicating algae...?


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## tiger15 (4 Jun 2022)

John q said:


> I beg to differ. Glutaraldehyde kills fish, anybody dosing 5x  standard dose is playing Russian roulette with there livestock.
> Maybe a close up photo of fish of fish subjected to 5ppm~ 10ppm long term of glutaraldehyde will sway my judgment, I suspect we won't get photos.
> View attachment 189503


I have compiled the toxicity data of Glut from various sources below, and you can judge how toxic Glut is.  For reference, Seacam recommends 2 ppm initial dosage after water change, and 0.4 ppm Glut daily thereafter.  The  initial dosage is  5x the daily regular dosage.  Seachem Paraguard ick remedy calls for dosing 4 ppm Gut, 10x daily dosage.

Toxicity of glutaraldehyde
96h acute Bluegill sunfish                    LC50 = 11.2 mg/L
Bluegill sunfish                        NOEC = 10 mg/L
48h acute Oyster larvae                    LC50 = 2.1 mg/L
96h acute Green crabs                    LC50 = 465 mg/L
96h acute Grass shrimp                    LC50 = 41 mg/L
48h acute Daphnia magna                    LC50 = 0.35 mg/L
Daphnia magna                        NOEC = 0.32 mg/L
96h algal growth inhibition Selenastrum capricornutum     ILm = 3.9 mg/L 
Algal inhibition Selenastrum subcapitata            IC50=1 to 1.8 mg/L
96h algal growth inhibition Scenedesmus subspicatus    EC50 = 0.9 mg/L
Bacterial inhibition Sewage microbes            IC50 = 25-34 mg/L
96h O. mykiss (Trout hatch  rate)                IC50 = 1.82 mg/L
96h C. dubia (Daphnia reproduction)            IC50 = 4.7 mg/L

*EC=Effective concentration;  IC=Inhibition concentration; LC=Lethal concentration; 
NOEC=No observed effect concentration


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## John q (4 Jun 2022)

tiger15 said:


> Toxicity of glutaraldehyde
> 96h acute Bluegill sunfish LC50 = 11.2 mg/L
> Bluegill sunfish NOEC = 10 mg/L


So... 11.2 ppm kills hardy fish in 96hr, And you feel comfortable dosing 2ppm in your aquarium, 👍 seems like a safe bet..


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## John q (4 Jun 2022)

Tim Harrison said:


> Isn't it better to concentrate on growing healthy plants than eradicating algae...?


😀


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## dw1305 (5 Jun 2022)

Hi all,


Tim Harrison said:


> Isn't it better to concentrate on growing healthy plants than eradicating algae...?


Yes.


tiger15 said:


> I don't think there is anything wrong dosing chemicals prophylactically to aquatic garden as homeowners regularly dose herbicides to their lawn.


And that is morally wrong <"on so many levels..............">,

cheers Darrel


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## tiger15 (5 Jun 2022)

Tim Harrison said:


> Isn't it better to concentrate on growing healthy plants than eradicating algae...?


Yes, the focus should be to grow healthy plants rather than to eradicate algae.  Same with lawn maintenance in that growing healthy grass will crowd out weed,  and you I’ll not win the war on weed by focusing on  weed eradication.


dw1305 said:


> Hi all,
> 
> Yes.
> 
> ...


I love unmowed European lawns that mix in flowers, prairie and weeds that are ecologically friendly to  insect and wildlife.   But in US,  not mowing down your urban lawn is illegal, yet it is legal to own machine guns to mow down people.


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## jaypeecee (5 Jun 2022)

zozo said:


> Most if not all truly aquatic plants will not take chemicals like glut and peroxide very well their tissue is too soft and gets damaged.


Hi @zozo

Occasionally, I have had cause to use H2O2 in my tanks at 2mg/l with no adverse effects. Tanks have had Java Ferns in them. No livestock. What would you recommend as a maximum H2O2 concentration with Java Fern?

TIA.

JPC


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## sparkyweasel (5 Jun 2022)

tiger15 said:


> But in US, not mowing down your urban lawn is illegal,


ah yes, 'the land of the free'. 
I wonder what would happen if you told City Hall it's not a lawn. it's a wildflower meadow?


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## jaypeecee (5 Jun 2022)

sparkyweasel said:


> I wonder what would happen if you told City Hall it's not a lawn. it's a wildflower meadow?


Hi @sparkyweasel

 

JPC


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## tiger15 (6 Jun 2022)

sparkyweasel said:


> ah yes, 'the land of the free'.
> I wonder what would happen if you told City Hall it's not a lawn. it's a wildflower meadow?


Yes, this has happened before, and was on TV news.  The neighbors complained.  Turning the lawn into  a meadow is no excuse for not mowing the lawn the  township ordinance prohibits.     The concern is not just neighbor complaint but invitation of thief to break in apparently unoccupied house.


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## PARAGUAY (6 Jun 2022)

I could hardly get my head round this the government in UK have just given the green light for another year for the use of pesticide Thiamethoxam?.despite objections from Health and Safety experts  this chemical theoretically one teaspoon is enough to eradicate 1.2 billion bees. Source the  Wildlife Trust


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## zozo (6 Jun 2022)

jaypeecee said:


> Hi @zozo
> 
> Occasionally, I have had cause to use H2O2 in my tanks at 2mg/l with no adverse effects. Tanks have had Java Ferns in them. No livestock. What would you recommend as a maximum H2O2 concentration with Java Fern?
> 
> ...



Sorry I have no idea, last time I did use peroxide in a tank with Java fern is in my High Tech years and that was years ago and only did spot treatment with 1ml 3% peroxide per spot. Never experienced any damage to the Java ferns. I always waited for it to stop reacting before treating another spot. Afaik, once it's no longer reacting it turns into water and oxygen and is no longer peroxide.

A few years ago I once did treat a complete small fishless planted tank with peroxide that was infested with Clado. Followed by blackout for 5 days, I remember it worked a treat and about all Clado was killed off for a while.  But actually don't remember the dosage and don't even remember if it had any Java ferns.

Also used peroxide in a spray bottle to mist plants with peroxide during a water change when all has emerged.

It all works, but always only temporary... Proverbially like, putting sticky plaster on a wooden leg? ( In my language we say, mopping the floor with an open tap). In other words, a waste of energy, a wild goose chase, a snake oil that works but isn't the solution. 

So I stopped using peroxide for that purpose years ago and have to agree with and stand by @Tim Harrison 's rhetorical question.

"Isn't it better to concentrate on growing healthy plants than eradicating algae...?"


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## jaypeecee (6 Jun 2022)

zozo said:


> In my language we say, mopping the floor with an open tap...


Hi @zozo

Excellent! And thanks very much for your reply.



zozo said:


> So I stopped using peroxide for that purpose years ago and have to agree with and stand by @Tim Harrison 's rhetorical question.
> 
> "Isn't it better to concentrate on growing healthy plants than eradicating algae...?"



It is undoubtedly the best option to concentrate on growing healthy plants. But, with the best will in the world, things don't always go as intended. That's when Plan B comes into operation. 

JPC


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## tiger15 (7 Jun 2022)

jaypeecee said:


> Hi @zozo
> It is undoubtedly the best option to concentrate on growing healthy plants. But, with the best will in the world, things don't always go as intended. That's when Plan B comes into operation.
> 
> JPC


True, things don’t always go as intended.  Among the fundamental rules  to grow healthy plants without algae are high plant mass, low organic load, adequate CO2, and no excessive light.

 When I started  my first planted  75 gal tank,  it’s too costly to fill up a big tank with high plant mass to begin with.   I keep messy cichlid with plants and don’t want to give up cichlid for shrimp  for the sake of minimizing bio load.  I also have a  1 gal planted shrimp bowl by the window that receives afternoon sunlight which I cannot dial down the intensity,  nor do I want to place a shade behind it that affects the visual.  CO2 is depleted due to intense sunlight and photosynthesis, but  I have no plan to inject CO2 into a 1 gal bowl.

Each of the above situations inevitably violates the fundamentals.  Glut and peroxide are helpful  when the fundamentals cannot be fixed.


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