# Allow algae to grow - yes or no



## LetDiceFly (May 30, 2008)

My question is this, should I allow algae to grow on the rear glass(acrylic) side of the tank (and the gneiss rocks where it's going to grow and is not practical to remove) . The rear of my tank is painted black, and I actually think that the algae looks nice and natural growing there. 

I have always assumed that having any algae anywhere in the tank will simply make it propagate and having more algae will cause it to do so at a faster rate. 

It has been implied in some posts that the algae should just be allowed to grow in part of the tank so it eats the excess/imbalanced nutrients, thus reducing the amount of algae growing elsewhere (the rest of the glass and on slow growing plants).

I'm not sure which of these opposing arguments are correct.

I have a low+ level of CF light in a 40 gallon tank with the typical low light plants java/anubias/crypts plus Amazon Swords (about 40 plants in all) and dose Seachem Comprehensive, Excel, and root tabs all according to the directions on the bottle. My tank is 97% stocked with fish according to AqAdvisor. 

I usually get GPA and GDA in the tank when maintaining/dosing my tank this way. Recently I had a period where I neglected my tank maintenance and had a massive outbreak of cyanobacteria. I left my tank blacked out for a while then cleaned the tank more than thoroughly. Just a week ago I added red bristlenose pleco to the tank, but he is only an inch long and I suspect he won't eat much. Right now after cleaning there is no algae in my tank except a little on some leaves that I couldn't get off. While I don't expect the cyanobacteria to reoccur I know from experience with my tank that the GPA or GDA will. Which is why I am asking this question.


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## niko (Jan 28, 2004)

If you have low light plants you should not be dosing anything in the water column. But in this hobby most people start with fertilizing even before putting water in the tank because they believe Tom Barr, a scientists that has convinced everybody that fertilizers are the way to run a planted tank.

You have already seen the problems with fertilizing the water - constant presence of algae in some form or shape AND a huge problem developing if you let the tank without "care" for a few weeks.

With your species of plants you can have a tank that you never fertilizer, never have issues, can leave it to evaporate half way and still have zero algae. How to do that is too simple to explain. Use common sense: Root tabs, clean water, minimum organics (perfect filtration), a low amount of injected CO2 and the tank will look great forever. Chances are the crypts will grow too well and force you to trim them about every 2 weeks.

About the presence of algae - it is up to you to leave them or clean them. Their presence in your tank shows that something is perpetually off. But more and more people actually start to like algae in a planted tank. If you like the look let them be. But don't by into the algae helping you "eat the excessive nutrients". You should not have any excess in the tank. In a properly setup tank the plants eat everything and there is no excess.


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## Zapins (Jul 28, 2004)

I agree with niko. Constant algae problems shows something is off in your tank. There are a few ways to deal with it, the high maintenance way of dosing fertilizers correctly and being in control of each parameter or using soil. 

There is nothing inherently bad about having algae. It is essentially just a lesser plant and it does the same thing for the most part. You don't need to remove the algae if you like the look. Also, I believe if you scrape algae off it does not have a huge impact on whether you get more or not. That really depends on the nutrients. If your tank is not in balance then you will get the same amount of algae whether you scrape once a week or leave it be. Algae eat nutrients and without those nutrients it cannot multiply no matter how often you disturb it.

Excel should help remove algae though.

Also, is Tom Barr actually a scientist or does he just call himself that? Some of his methods are not very scientific...


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## LetDiceFly (May 30, 2008)

Thank you for your responses. But the specific question (I probably worded it unclearly), I wanted an answer to was whether a tank with a small amount of algae left growing is more likely to have an serious algae bloom than one where effort is made to keep it cleaned off. 

I must disagree with the idea that the small amount Flourish and Excel (or without the Excel, I have done it both ways) will more likely cause runaway algae problems then no dosing, in my specific case because the major bloom of cyanobacteria mentioned, along with an increased amount GDA & GPA only happened when it was without fish and I thus stopped paying attention to it or putting the above ferts into it (for about 3 weeks). Lighting never changed though because it was on a timer (8 hours). Normally with the small amount of ferts I only get only a little algae or I probably wouldn't be considering leaving some in there. Even with slow growing plants I have great amount of growth with the recommended doses. Even with low+ (almost medium) light I have it so heavily planted that it must be using most of the modest amount ferts, or so I reckon.


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## niko (Jan 28, 2004)

All this cool talk about algae and fertilizers. This is in essence the US hobby.

Note one VERY important thing - we are yet to mention the word "filtration". Fertilizers this and fertilizers that and algae this and algae that. Draw your conclusion.

About a small amount of algae always being present. First off it is not normal but most people in this hobby believe it is. Second - look at it that way: You have a rash on your leg. It is small, just 1/4" in size. Is it ok to leave it be? Will it spread and take over? You decide. Except that algae are not a skin rash. They are actually more amazing than the cool plants we all love to fertilize so much. Look at the following two threads for a "new" way of looking at a planted tank:

http://www.aquaticplantcentral.com/...-plant-club/88624-aquascaping-way-should.html

http://www.aquaticplantcentral.com/forumapc/filtration/88696-you-need-read.html


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## Zapins (Jul 28, 2004)

LetDiceFly said:


> ....whether a tank with a small amount of algae left growing is more likely to have an serious algae bloom than one where effort is made to keep it cleaned off.


No. A small amount of algae left alone or cleaned off have exactly the same chance of causing a serious algae bloom. Algae blooms are a result of favorable tank conditions not the amount of algae present. If conditions are good you will have a serious bloom whether you clean it off every 10 minutes or every month.

Also, flourish excel is a known algae killing chemical.


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