# Green Spot Algae Cause/Control



## Naja002 (Oct 12, 2005)

Linwood said:


> I hope I've identified this correctly as Green Spot algae.
> 
> From what I see scraping it off is the main option, though I do have 4 Nerite snails they don't seem to be doing much with it. But what's causing it?
> 
> ...


I am currently dealing with GSA, and now Diatoms, in an ~1 month old setup. I have been keeping my PO4 in the neighborhood of 5ppm (2-8ppm) in an effort to drive off the GSA (the diatoms I'm not worried about). I cannot really tell if it is helping, but my photoperiod is lights on = 12 hrs <--that's 6 on-3 off-6 on. I've dropped my lighting from a 23w CFL to a 20w CFL...and, again, I cannot tell if that has helped much. However, the tank gets INdirect light from a nearby window....so, that may very well be the root of the problem. A couple of hrs ago I covered the side toward the indirect sunlight, so I'll have to wait to see what the outcome of that is. Next will be to drop my lighting down to a 15w CFL, unless I can find a quality 18w CFL. I _*like*_ the long photoperiod, so I am very reluctant to change it...only as a _last _resort! :hihi:

So, in short: There maybe any 1 thing or a combination of things at play for your setup. Look at the individual aspects - sure, but take a look at the bigger picture too. High PO4 is not an issue....just keep in mind that high PO4 may allow your plants to utilize all of the nitrates and/or potassium, so you may want to make sure those numbers are up also. roud:

As a side note: It's _supposed _to be a low tech setup, so that is why I have been dropping the light wattage. I do use metricide and have been overdosing it, but have backed off of the overdosing recently.


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## Linwood (Jun 19, 2014)

Naja002 said:


> High PO4 is not an issue....just keep in mind that high PO4 may allow your plants to utilize all of the nitrates and/or potassium, so you may want to make sure those numbers are up also. roud:


I do not explicitly dose either potassium or phosphates, just what comes in Eqilibrium as I make up new RODI water for (infrequent) changes.

I have both, I could does -- do higher levels help?


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## Naja002 (Oct 12, 2005)

Linwood said:


> I do not explicitly dose either potassium or phosphates, just what comes in Eqilibrium as I make up new RODI water for (infrequent) changes.
> 
> I have both, I could does -- do higher levels help?


Supposedly, Yes. However, My main issues with GSA were on a super high light, high tech setup, so I'm not really sure anything would have helped. :hihi: And, now on this low tech setup. I seriously think the root of the issue for me is that added indirect sunlight, but we'll see.

The GSA that I have is not bad on the glass, but it is mainly only on the 2 panes that the indirect sunlight hits. Most of it is on the rocks and anubias leaves. However, again, high PO4 is not an issue....just make sure it does not allow your plants to suck up all of the nitrates, potassium, etc.

I use exclusively RODI also. Currently it comes out at 1-2ppm. Once I change out a DI cartridge...it will run 0ppm for months. Anyway, I was dosing everything and testing to get a feel for this setup. 2 weeks ago I added 9 small Tiger barbs and have been testing to see what the effect of feeding them is. So, I am mainly dosing micros, extra K, and then on WC day...I test N and P to see where things are at. Last weekend I did not dose any N or P, this week I dosed some of everything just to bring the numbers back up. So, a lot of it will depend upon whether it is a planted only tank or if you have livestock. If you have livestock then you will want to account for their food/waste.

Personally, on both of my low tech setups...they are using much more ferts than I would have guessed, but, again, I have been overdosing metricide, so now that I am backing away from that....the fert usage may drop some.

Not sure if this will ease any conncerns you may have, but here it is:

5ppm 3x a week


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## latchdan (Sep 7, 2007)

Gsa generally caused by high light and low phosphates.Seeing it on anubias is normal in a high light tank,the plant is a slow grower. If you can shade it,that might help.
I am on my phone so cant see the picture very well.


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## Solcielo lawrencia (Dec 30, 2013)

GSA usually a sign of low PO4. Increase PO4 and it will go away in a couple of weeks.


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## tetra73 (Aug 2, 2011)

Prolong lighting period or too strong light with low PO4==GSA.  Keep PO4 around 3 ppm in a low tech tank. Don't exceed your lighting period for more than 8 hours. In a high light, high tech tank, I need to keep my PO4 from 5ppm to 10ppm to control GSA.


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## Linwood (Jun 19, 2014)

tetra73 said:


> Prolong lighting period or too strong light with low PO4==GSA.  Keep PO4 around 3 ppm in a low tech tank. Don't exceed your lighting period for more than 8 hours. In a high light, high tech tank, I need to keep my PO4 from 5ppm to 10ppm to control GSA.


Could you elaborate on where you got the 3ppm?

I am reading the Seachem bottle (admittedly not labeled "this is the gospel truth") and it says "The ideal phosphate level will vary but generally ranges between 0.15 and 1.0 mg/L", which puts their high end a third of your low tech recommendation.


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## Luis Batista (Sep 8, 2014)

tetra73 said:


> Prolong lighting period or too strong light with low PO4==GSA.  Keep PO4 around 3 ppm in a low tech tank. Don't exceed your lighting period for more than 8 hours. In a high light, high tech tank, I need to keep my PO4 from 5ppm to 10ppm to control GSA.


Thats ok to increase the PO4 to that level?
I already dose about 3ppm a week but still have alot of GSA.

Enviado através da ponta dos meus dedos!


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