# [Wet Thumb Forum]-algae growth - low tech solution?



## graham1212 (Oct 13, 2004)

is getting algae eating fish really a solution to a large algae problem? i hear the best way is to make sure the plants have all the nutrients they need in the correct quantities so that there is no excess for algae to take advantage of and so the plants consume everything properly. is this possible withour fertilization? just looking for some ideas/suggestions

graham


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## graham1212 (Oct 13, 2004)

is getting algae eating fish really a solution to a large algae problem? i hear the best way is to make sure the plants have all the nutrients they need in the correct quantities so that there is no excess for algae to take advantage of and so the plants consume everything properly. is this possible withour fertilization? just looking for some ideas/suggestions

graham


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## Tonka (Mar 20, 2004)

Once I got PO4 to 0.5-1.0 ppm and NO3 to 5.0-10.0 ppm, my algae forest stopped growing, turned dark green and peeled away from the driftwood, and didn't grow anymore on new growth. As I pruned away the old growth with the algae, my tank looked better immediately. But I inject to achieve CO2 of 20-30 ppm!

I really can't understand how a nutritious water column can't also feed algae. I don't understand this competition business.

I don't mean to be a wiseass, but if your water source is blessed with a nitrate / phosphate ratio of about 10 to 1, your water has a low KH (any CO2 available is not bound up), and you change your water frequently, my guess is that you'll have no algae.


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## aquabillpers (Apr 13, 2006)

Hi,

The best way to contain algae is to have healthy, growing plants. This is accomplished in a natural aquarium by having a good substrate, reasonble light, and by feeding the fish well. If you do that, long term, algae will not be an issue.

As I understand it (and that understanding is limited), algae can prosper on fewer nutrients and lower light levels than can higher plants.
So fertilizing the water column helps those plants to prosper and eventually outcompete (yes, outcompete) the algae for the limiting nutrients.

Bill


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## dwalstad (Apr 14, 2006)

> quote:
> 
> Originally posted by graham1212:
> is getting algae eating fish really a solution to a large algae problem? i hear the best way is to make sure the plants have all the nutrients they need in the correct quantities so that there is no excess for algae to take advantage of and so the plants consume everything properly. is this possible withour fertilization? just looking for some ideas/suggestions
> ...


I don't add chemical fertilizers to my tanks.

My plants get what they need from the soil substrate, which is constantly enriched by recycled fishfood. Since algae doesn't have access to soil substrate nutrients (especially iron), the plants have an advantage over algae. The plants (fortified by substrate iron) can simultaneously drain nutrients from the water and deprive algae. There's no need to add nutrients (especially iron!) to the water.

My book has a whole chapter on algae control. Algae-eating fish may help control some forms of algae but vigorous plant growth is your best bet.

Two caveats:

(1)For hobbyists with softwater AND poor plant growth, I recommend fertilizing water with what I call "the hardwater nutrients" (that is, calcium, magnesium, and potassium). If your water is hard (GH of 8 or greater), this shouldn't be necessary.

(2) Hobbyists that have CO2 injection often need to add iron and nitrogen fertilizers to maintain good plant growth that can compete with algae. This is often an effective strategy for them. However, this requires (in my opinion) considerable work/expense, and the tank becomes increasingly artificial.


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## kenmeyer (Jul 31, 2004)

I also had a algae problem in my tank. I would keep the front of the tank clean but the back and sides and some of the plants were covered it didnt bug me much becouse the plants were still growing and the fish were happy. But I decided to see if I could come up with some kind of easy answer. I bought 2 cory cats, 2 large white snails, 1 chineese algae eater and 1 fish that looks like a flounder"sorry dont know what its called I bought it becouse it looks cool" I put these all in the tank and within 3 days they cleared almost all the algae off the glass infact alot of it got knocked on the gravel, I had to vacuum off the debree of the gravel.And after about two weeks the glass is clean and so are the plants. Plant growth rate is faster also. On a side note I also increased the water movement in my tank to get stuff moving around alittle. I wish I would have done all this long ago this is the easyist tank and most sucsessfull tank ive ever done.


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## dwalstad (Apr 14, 2006)

It sounds like you did the right thing for your tank. Similarly, I had a little blue-green algae in my 55 gal. Plants were doing okay but the algae was making it tough for them. I added a single treatment of Maracyn (erthromycin) and it killed the algae within a day or two. Now two weeks later, algae is totally gone and plants are doing much better!

In summary, sometimes when plant growth is being held back by algae, it may help to use a trick or two like the one you've described. Once you get past this "tipping point", plant growth should become strong enough to check algal growth.


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## aviel (Sep 12, 2004)

Diane,

Concerning your single maracyn treatment. Shouldn't any antibiotic treatment last at least couple of days after visible BGA? I mean - just to make sure that it's completely whipped off? I think this is the recommendation for humans taking antibiotics.

Aviel.


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## dwalstad (Apr 14, 2006)

Aviel,

I'm can't give a definitive answer on this, but it is a very good question. Technically and accordingly to conventional wisdom, you are probably right.

However, I think there's a little leeway. In a healthy tank with good plant growth (which is what I had), a brief treatment that kills 99.9% of the algae may be enough. Enough to tip the balance for the plants. I've not seen a speck of blue-green algae in this tank since the treatment. 

I believe that good plant growth is the main, long-term defense. 

Likewise in a healthy human with a lingering infection, a brief shot of antibiotics that kills 99.9% of the infectious bacteria may be all that is needed. The immune system can take care of the rest.

One reason I question conventional wisdom on antibiotics is that USA farmers feed their livestock with tons of antibiotics. And they don't have to get a prescription!


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## Josh Simonson (Feb 4, 2004)

The argument for doing the full AB treatment is that partial treatments, over time, may selectively breed AB resistant bacteria. I don't think that the comparison of algae to human diseases is very good. The diseases occur mainly in people, so a goodly part of the total population is regularly introduced to antibiotics, wheras algae (and other bacteria in the aquarium) grows the world over and only the tinyest fraction ever meets it's LD50 of antibiotics. This means that any slightly AB resistant genes would be quashed by the wild genes and not further develop into 'superbugs'.


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## dwalstad (Apr 14, 2006)

> quote:
> 
> Originally posted by Josh Simonson:
> The argument for doing the full AB treatment is that partial treatments, over time, may selectively breed AB resistant bacteria. I don't think that the comparison of algae to human diseases is very good. The diseases occur mainly in people, so a goodly part of the total population is regularly introduced to antibiotics, wheras algae (and other bacteria in the aquarium) grows the world over and only the tinyest fraction ever meets it's LD50 of antibiotics. This means that any slightly AB resistant genes would be quashed by the wild genes and not further develop into 'superbugs'.


Good point. It reminds me to stay "on topic".


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## Maurici (May 31, 2004)

Diana posted:The plants (fortified by substrate iron) can simultaneously drain nutrients from the water and deprive algae.
I agree, of course, but I would like your opinion about the result of a possible disiquilibrium by increase of light. I will like more light to my tank and I'am engaged in a slow increase (to avoid photoinhibition in the plants), but my doubt is if it can be exploited by algae. Your comment, Diana, goes pointing out no problem coming because the algae can be still deprived on the other nutrients, but one paradigm says that an increase of light imply higher demands of CO2 and nutrients that if are not supplied conduct to a sink of the plant community.
Maurici


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## dwalstad (Apr 14, 2006)

Dear Maurici,

You are doing the right thing- finding out how much light gives you the best results for your tank. No one else can do this for you. 

I wouldn't worry about light causing an increase in plant demand for CO2 or other nutrients.

You want to provide enough light for good plant growth but not enough to stimulate algae. Remember that submerged aquatic plants are basically shade plants; they can only use so much light.


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## Maurici (May 31, 2004)

Thank you Diana for your comments







.
Kind Regards.
Maurici.


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