# Strategy for combating Green Spot Algae (GSA)



## pelicanincident (Mar 5, 2013)

If I've had a serious GSA problem on the leaves of my Ludwiga for the last few months, and I know I've finally got the water parameters where I want them. Obviously you have to physically remove the existing algae from the tank. Should I be more liberal about pruning leaves that are starting to get overrun with GSA, or leave only semi-affected ones alone for a while? GSA seems quite persistent, making me think that I need to really prune it into submission in order to actually get over the hump.


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## acitydweller (Dec 28, 2011)

GSA is likely attributed to an excess amount of light and nutrients. pruning will not stop the algae from spreading. how long is the photo period and what type of lamp is used? how much light in terms of wattage is being applied to what sized tank?


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## plantbrain (Dec 15, 2003)

High CO2 and high PO4, not much of an issue then. Folks figured this out maybe back in the late 1990's.


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## happi (Dec 18, 2009)

are you sure its not GDA? some people think GDA is GSA. do you have any close up picture of your tank?


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## Flear (Jul 10, 2013)

green dust "algae" vs green spot algae, ... one falls off the glass easily, the other needs a pleco or a razor to get it off the glass.

Edit:
very easy to identify the difference
-one is fluffy
-the other is stuck to the glass


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## pelicanincident (Mar 5, 2013)

Finnex Ray 2 24", about 18 inches above substrate on a 20 gallon high. 8 hour photo period. I just finished the process of increasing my pressurized CO2 to the point where the fish are having trouble breathing, then knocked it back a hair. So I know my CO2 is at its maximum. EI dosing, whenever I test my phosphates they're always between 2-3ppm.

Its GSA, its not fluffy at all.

Should I move my light up a little bit? I have high CO2 and PO4. The thing that's so hard to do in these situations is have patience. Obviously you can't see if the algae is spreading at higher or lower rate in a day, or a few for that matter.

I'll post a picture tonight.


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## Flear (Jul 10, 2013)

careful about your CO2

higher lights the plants can process more CO2.

but there is also a point were it's too much and it goes toxic for the plants

certain terrestrial plants (with temperatures raised so they can metablize faster, with higher lights so they can process more)

1200ppm CO2 is max usable
1500ppm CO2 is max before it gets toxic to the plants

i do not know what it's like for other plants
i do not know what it's like for aquatic plants underwater

Edit:
more is not always better


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## pelicanincident (Mar 5, 2013)

Here is a photo of the GSA on the Ludwiga leaves: 









Here is a photo of my tank to give you a sense of my light level:


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## Flear (Jul 10, 2013)

do you have staghorn algae in your tank ?


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## pelicanincident (Mar 5, 2013)

I don't think so, although I assumed that is BBA on the edges of the leaves because its darker in color and doesn't get very long.


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## gSTiTcH (Feb 21, 2013)

Flear: you will kill your fish before you kill your plants with CO2.


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