# What's wrong with using an algaecide?



## banderbe

I've seen lots of people on this forum and others advise against the use of algaecides such as AP's Algae Destroyer Advanced product, but other than possibly killing off some of the biological filter bacteria I don't see any other reason not to use it and if you follow the directions it's pretty near impossible to kill your biological filter bacteria anyway.

Obviously an algaecide is not a long term solution. However, like other often prescribed solutions such as a blackout, bleach dips, or hydrogen peroxide it seems a perfectly viable short term solution to an algae infestation.

So, what are your thoughts on the use of algaecides as a short term solution to getting algae under control?


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## gibmaker

They work, to a certain degree, but can also have effects on small sensitive plants. If you have inverts, it is not an option as most algecides will kill them.


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## Salt

If you _have_ an algae outbreak, you should try to identify the cause and correct it, rather than just rely on the algaecide.

However, if you _are_ working to correct the cause, then I feel there is absolutely nothing wrong with using an algaecide to get rid of existing algae.

Algae Destroyer may harm some plants and will kill shrimp. I would recommend AlgaeFix first in a planted tank, which in my experience is extremely good at clearing water cloudiness due to algae blooms.


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## Cavan Allen

I agree that fixing the cause of the problem is the best way to approach algae issues. I'll add that having all your bases covered will usually prevent problems from even happening in the first place. 

However, using chemicals to kill algae (except, perhaps, for Excel) can have extremely deleterious effects on both flora and fauna. Why go through the risk and expense when there are safer and easier methods available?


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## BryceM

There may be an appropriate place for some algicides in certain circumstances, but a great many of them can be quite harmful. They often contain copper, which can be quite toxic to inverts and even many of the plants we try to keep. Unless you understand the ingredients, I would recommend extreme caution before dumping a comercial algicidal product into a tank.

Algicides are toxins. That's how they work. The toxic effect often extends beyond the intended target.


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## Linda

i understand and agree with what you are all saying, however in some cases there is nothing being done wrong. such is the case of well water. sometimes no matter what you try it just doesn't get rid of algae. i know when i lived in the city i never had algae but since my move to the middle of nowhere and well water, i have had a constant algae situation which i can't stand. i have a planted tank and a 90gal mbuna tank. i have just had to deal with the algae as i don't want to kill the plants in my 29gal planted/fry growout tank. but the other tank i have often wondered if the products you are discussing would work or what the fall out might be for the fish. this is a good discussion and i am looking forward to what people have to say.


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## bigtroutz

Something to keep in mind is that *everything* is toxic. Water, CO2 and oxygen are toxic to a lesser or greater extent, depending on the species and concentrations. However, nobody is going to want to have an aquarium for aquatic plants and fish without water, sufficient oxygen and CO2 to keep everything "happy".

If you wish to try using algaecides in your aquarium, by all means have at it, as long as you are aware of the law of unintended consequences. I am sure you can find some plant and fish species that will survive the application of the recommended dosages of some algaecides just as you will find other species that kick the bucket. You will also likely find some species of algae that will thrive in the treated environment as well, rofl.


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## Laith

I see three problems with algaecides:

- They are meant to kill algae which is basically a "primitive" plant form. So whatever is in the algaecide that will harm the algae *will* have an effect on all plant life. Sometimes this effect is minimal, sometimes not.

- More often than not they are "magical" snake oil products and beginners grab them and start pouring this stuff into their aquariums. When that doesn't work, they pour more in until the tank crashes.

- The very few products that actually work can become a trap: "Oh well, looks like that BGA is coming back... I'll just do another round of Erythromycin and that'll keep it away for the next x months"  . While this may work, I'd guess that even with careful and knowledgeable use of a proven product, long term continual use (even intermittently) can't be good for an aquarium.

I've always found that fighting algae is a two pronged approach: removing existing algae and fixing the underlying problem. Removing existing algae can be manual or with a product. There's nothing really wrong with using a tried and tested product (with known ingredients!) to help with the removal of the existing algae... as long as one is aware of the potential downsides and treats the product accordingly.

So far the only products that I have used that do the job on certain algae and when used correctly have a minimal negative impact on the aquarium are Erythromycin and Excel. I've never tried Hydrogen Peroxide so can't comment on that. None of these are snake oils.


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## AaronT

I'm a fan of using Excel or H2O2. Both are easily dilluted by a few water changes if the levels get too high and then they are no longer harmful to fish and fauna. 

As stated above, the algaecides are toxins and are not as easily removed once introduced into the tank. I've tried it before early in my planted aquaria start and it does affect plants in a negative way.


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## furballi

Quick 1 minute dip in diluted bleach (19:1) is very effective at removing algae. Anubias can tolerate two. Immediately rinse the treated plant under luke-warm tap water. Remove dead algae with toothbrush if possible.


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## Cavan Allen

Linda said:


> i understand and agree with what you are all saying, however in some cases there is nothing being done wrong. such is the case of well water. sometimes no matter what you try it just doesn't get rid of algae. i know when i lived in the city i never had algae but since my move to the middle of nowhere and well water, i have had a constant algae situation which i can't stand.


I know that well water can be really bad, but all you really have to do is do _whatever you have to do_ to get better water. If that means an RO system, then so be it. Once that's resolved, the same practices that worked with city water will work again.


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## Tonka

These posts reminded me that since I no longer have shrimp I can try Algaefix. Yesterday, I did my monthly 50% water change and added a dose. My plan is to leave everything else exactly the same and especially not to add any more Algaefix, even though the manufacturer recommends a regimen.

Daily adds of NO3 (1.0ppm), PO4 (0.3ppm), K (0.6 ppm), Fe (as CSM+B, 0.2ppm), 2X dose of Excel. Base ferts, 10, 1, 10, and 1, respectively.

As a former product manager for a herbicide, I am not reluctant to use Algaefix (per se) as a tool in my repetoire. Everything we add to our tanks is a chemical or mix of chemicals, including fish and plants! We use Excel as an algaecide, but Seachem would rather have knowledge of this use spread by word of mouth (legal) rather than actively promote it (illegal) before undergoing expensive testing.


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