# Truth about Green Dust Algae?



## Manwithnofish

Truth About Green Dust Algae?

My recent experience with GDA leads me to believe that no one knows definitely how to put an end to GDA. That’s ok, it’s a living thing and that makes it complex enough that I can appreciate that it doesn’t fall into the Easy category. Shame on me for thinking, it's a problem (like a flat tire) and I just want instructions on how to fix it.

So, shouldn't we just admit that we don’t know how to get rid of it.

What is the most accurate statement that we can make about GDA?

a. We (the aquarium hobbyist) fully understand the factors that cause GDA and know how to get rid of it. A specific set of directions, if followed will be successful in defeating GDA, 100% guaranteed.

b. We fully understand the factors that cause GDA and know how to get rid of it, but only under certain specific situations and conditions.

c. We do not fully understand the factors that cause GDA, but can offer some suggestions that may or may not work. Successful solutions vary. What works for one individual will not work for everyone. 

d. We do not understand the factors that cause GDA and accept that you may not be able to defeat GDA. The best you can hope for is to control GDA by vigilant cleaning and good housekeeping. It is not known why GDA eventually goes away. It appears that it either dies or goes into long dormant states. Neither of which happens as a result of anything that you do. 
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## Zapins

I think c is probably the single most accurate statement, but we probably know a little more than that, so in reality the truth somewhere between c and b. 

As for the cure - many people have killed if off in slightly different ways, but the ones that tend to be most successful all seem to revolve around letting it run its course for 2 weeks (without touching it), then scraping and removing it with a water change, and/or reducing the light duration (7 hours & less intense lighting) and intensity for 2 weeks and doing water changes.

Ultimately, it is not invincible and you will eventually get rid of it, although it is probably one of the worst and most disheartening algae types to get (second in difficulty to remove only to a severe infestation of BBA).


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## bsmith

I think that GDA/GDA is a necessary evil in our hobby. 

We can limit it by what Zapins has mentioned, shorter photo period, light higher off the surface of the tank. Maybe the perfect balance of ferts but that remains to be seen.

I am content with cleaning the glass once a week with my water changes and have accepted this as a side effect of having a high tech high light tanki.


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## Manwithnofish

Zapins said:


> I think c is probably the single most accurate statement, but we probably know a little more than that, so in reality the truth somewhere between c and b.
> 
> As for the cure - many people have killed if off in slightly different ways, but the ones that tend to be most successful all seem to revolve around letting it run its course for 2 weeks (without touching it), then scraping and removing it with a water change, and/or reducing the light duration (7 hours & less intense lighting) and intensity for 2 weeks and doing water changes.
> 
> Ultimately, it is not invincible and you will eventually get rid of it, although it is probably one of the worst and most disheartening algae types to get (second in difficulty to remove only to a severe infestation of BBA).


I am aware of the successes that some people have had with this method or that method. I've seen many suggested remedies. I myself have tried all those you mentioned above, raised lights, reduced period, did not touch the tank for 4 weeks, etc, etc....and GDA came back in my tank within 5 days. So for me the answer is more like c or d.

My point is just because a particular solution works for some, why doesn't it work for every one? We all have essentially the same toybox...water, light, chemistry, nutrients, biology. So maybe we know it well but not completely. Is it not the same as a garden? Not every one can grow carrots the same.

Certainly, I'm not the only one who has difficulty in understanding and defeating GDA. I REALLY don't believe that people KNOW more that the rest of us. Maybe there's just a little bit of luck involved. Theoretically, if enough people flip a coin, some one is going to flip heads 100 times in a row, maybe a 1000 times. Does that mean that they know how to flip a coin and the rest of us don't?


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## Manwithnofish

bsmith782 said:


> I think that GDA/GDA is a necessary evil in our hobby.
> 
> I am content with cleaning the glass once a week with my water changes and have accepted this as a side effect of having a high tech high light tanki.


Sounds like you're choosing "d" to me...so the question is, have we just quit trying, did we not follow the procedure correctly, did we do something wrong? Or, just maybe, the "cure" doesn't always work. Sounds like a disease. Certainly the medical community knows a lot about certain diseases but sometimes, you just have to be one of the lucky ones...same treatment...different results. I believe the truth is...that's all we know. If it works it works, and if it fails...oh well, go directly to "d" and live there.


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## Cavan Allen

In my experience, it's a nutrient balance issue, just like everything else. I've seen it occur with either too much fertilizing or too little. It's easy enough to fix and not the unstoppable force some people say it is.


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## Manwithnofish

Cavan Allen said:


> It's easy enough to fix and not the unstoppable force some people say it is.


In my experience, it's definitely not easy to fix. But anyway, I guess you are the "a" camp.


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## Zapins

Manwithnofish said:


> In my experience, it's definitely not easy to fix. But anyway, I guess you are the "a" camp.


Hehe  something about people splitting up into different camps over this is amusing to me 

Perhaps removal of GDA is all about the time frame you view your tank in. If you are someone who checks the tank daily waiting for each new leaf to emerge then GDA might be an eternity of pain, but if you are someone who worries about how well their anubias patch is going to fill in overa 1 foot piece of drift wood then GDA might seem trivial and very brief compared with other persistent types of algae.


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## Nevermore

Cavan Allen said:


> In my experience, it's a nutrient balance issue, just like everything else. I've seen it occur with either too much fertilizing or too little. It's easy enough to fix and not the unstoppable force some people say it is.


You say it's "easy enough to fix", maybe you can elaborate.


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## Supercoley1

I have only ever had GDA once. when I first began. These were the days when I tried to use DIY CO2 with high lighting and snake oils for ferts 

When I rescape these days I get nothing  IMO planting heavily from the outset once you know you have good flow, good CO2 and good ferts means it doesn't appear 

When I say heavily planting I mean that even the 'pros' can struggle with it on lightly planted tanks such as Iwagumis etc.

Peter Kirwan's mountainscape that won in the comps last year suffered and this was just HC and rock 

AC


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## hooha

If we have to pick camps, I'd have to go with C. 

Like Cavan said, it's an imbalance that promotes it. A specific imbalance likely can't be named.

I think with any algae, the amount of organics (mulm, fish load, dying plant matter from an imbalance and from algae overtaking it, etc) plays an important role.

I recently started up an automated system, initially after planting I had a nice plethora of algae, from thread algae to green dust algae, to hair algae. I did multiple, heavy water changes,removed dead/dying plant matter, removed as much algae as possible (including the GDA) and decreased my fert dosing, and the algae (including green dust) has resolved....


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## Newt

I'll say C with a leaning to D.

It was suggested to me to up my PO4 from 1 ppm to 2 or 3 ppm. All that did was increase the issue. I read an article by Tom Barr who was talking about a balance of PO4 and CO2. The higher CO2 concentrations needed less PO4. blah...blah...blah.

If all water sources were identical in composition/make-up then we could easily find the solution for all. However, nature hasnt been so 'regular' and what works for one will not/may not work for another with anything in this hobby.


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## goldfishes

Newt said:


> I'll say C with a leaning to D.
> 
> It was suggested to me to up my PO4 from 1 ppm to 2 or 3 ppm. All that did was increase the issue. I read an article by Tom Barr who was talking about a balance of PO4 and CO2. The higher CO2 concentrations needed less PO4. blah...blah...blah.
> 
> If all water sources were identical in composition/make-up then we could easily find the solution for all. However, nature hasnt been so 'regular' and what works for one will not/may not work for another with anything in this hobby.


These last two sentences says it all.


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## Nevermore

Newt said:


> It was suggested to me to up my PO4 from 1 ppm to 2 or 3 ppm. All that did was increase the issue. I read an article by Tom Barr who was talking about a balance of PO4 and CO2. The higher CO2 concentrations needed less PO4. blah...blah...blah.


Well, increasing the PO4 is usually recommended for G*S*A, not G*D*A.

I'm in the "c" camp btw.


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## Evil-Lynn

I guess I go with the "c" option. I mean you can wipe off all you want but it doesn't guarantee it won't come back. :-k
I myself got some of it in my Low Tech tank. I read somewhere that you should wait for it to end its life cycle. In other words it dies on its own. So I did that plus I added more plants. In 3 weeks, the entire green thing turned white. I decided to wipe it off. I dunno if it died on its own or if the extra plants helped but it has been 2 weeks and it hasn't come back.

I am not too paranoid if it does come back. I mean I do clean my tank every couple of weeks, removing debris and whatnot. Doing a bit of wiping is not that bad. At least it's not as hard to remove as BGA, GSA or BBA. Now those are real nightmarish...


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## Newt

Nevermore said:


> Well, increasing the PO4 is usually recommended for G*S*A, not G*D*A.
> 
> I'm in the "c" camp btw.


Well, lets see. I increased my PO4 slowly to combat green spot on my plants. It got worse and the GDA, on the tank glass, got better. No other changes. I went back to my 0.5ppm PO4 and the GSA got better and the GDA got worse just like it had been.

If all water sources were identical in composition/make-up then we could easily find the solution for all. However, nature hasnt been so 'regular' and what works for one will not/may not work for another with anything in this hobby.


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## Supercoley1

was the only change you made to add more KH2PO4 powder into the tank? or did you change anything else at all?

Sometimes there is something else that happened at the same time and people assume it was the factor they were aiming to alter that brought about the result.

I don't get GDA whether I increase or decrease PO4 however if I decrease the PO4 I get more GSA. Up it and I get less. Up it too much and I get more plus cloudy water.

There is IMO a balance for PO4 rather than being able to throw in as much as you want.

AC


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## Newt

I only increased the phosphate level.


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## Zapins

You want to know the truth about green dust algae?

......Its EVIL!

That is all


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## Newt

Persistant at any rate.
I have more of an issue with green algae (GSA?) on the plants. At least the GDA can easily be scraped away.

All algas are EVIL:mad2:


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## Nevermore

My GDA is on the plants as well as the glass. It makes it much more of a nuisance. I'm decreasing the photoperiod to see if I can get rid of it.


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## Newt

I'm not sure which green algae is on (some) of my plants. All I know is that it is green. I also cut back on duration and cut out my midday burst. It has helped a bit.


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## rich815

Newt said:


> I'm not sure which green algae is on (some) of my plants. All I know is that it is green. I also cut back on duration and cut out my midday burst. It has helped a bit.


Rub a leave that has it between your fingers. If it's slimy it's likely not GDA and could be a type of BGA (cyanobacteria).


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## Newt

It is definitely not BGA.
The texture is a bit rough.
I wouldnt recommend touching cyanobacteria as it contains hepatotoxins (liver toxins).
This algae usually only shows up in polluted tanks (high PO4 and other nutrients) and feeds off of light heavy in the yellow/orange zone (~600nm +/-) where phycocyanin peak absorbtion occurs. Neither of which I have. Plus I dont have that manky odor either.


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## Zapins

Newt, just to clarify is that graph for the cyano or for the dust algae? I've never read about that before, pretty interesting stuff, do you have a link to a larger article? I'd like to read more about it.


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## Supercoley1

if it is rough it is more likely another algae and not GSA. Is it flat to the leaf? AC


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## Newt

Zapins said:


> Newt, just to clarify is that graph for the cyano or for the dust algae? I've never read about that before, pretty interesting stuff, do you have a link to a larger article? I'd like to read more about it.


The graph is for plant photosynthesis absorbtion rates for the different chlorophyll and such that plants use in the photosynthesis process. I think I got this graph off of a university website site that was doing experiments on photosynthesis. Over the years I have collected many different graphs while researching plants and lighting. I'll see if I can find the website. It was a good article as I remember.


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## Newt

Supercoley1 said:


> if it is rough it is more likely another algae and not GSA. Is it flat to the leaf? AC


Not sure what you mean by flat to the leaf. I just call the stuff plain green algae that grows in healthy water.


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## Supercoley1

Gsa is very thin and grows like a birthmark on the leaf. It doesn't raise away from the leaf at all. It is flat sort of like a discolouration of the skin. A Dark green mark on the leaves. Normally on Anubias you can see some in even the most perfectly balanced tanks.

If it protrudes from the leaf at all then it isn't GSA.

AC


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## Newt

I would say it has a textured surface. The SAE's, Otos and pleco eat it. Its on my Bacopa monneri, anubias and some rocks. It may or may not be all the same species but they are all green. Perhaps it is GDA. I do know I will sometimes get GSA on the rear glass as this is definitely spots and is different than the green stuff on the sides and front of the tank glass.

At any rate I have not conquered this yet.


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## Supercoley1

That means it isn't GSA. Otos won't eat GSA. A picture would enable us to ID it for you 

AC


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## Newt

Thanks.
I'll try to get a pic of the Bacopa this weekend. It's a busy weekend but I'll try to fit it in.


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## Newt

Here's a pic of the lower leafs on my Bacopa. Its not showing up anymore on the top since stopping the midday burst.


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## AheartlessFish

I'll take cleaning GDA over GSA or BBA any day ^^ 

My experience with GSA has probably something to do with the intensity of the lighting. Having my halide raised above the tank and other tanks next to the main tank (with the halide), i can see that the side of my other tanks are hit with GSA in certain spots where the Halide beams towards. No big deal, scrub scrub. In my other tanks that do not have halides but t-5's, i have no issues with this algae.


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