# Green spot algae



## Characins

What causes green spot algae?

And how do you get rid of it/prevent it?


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## rich815

Supposedly low phosphate. But I'm at 5ppm and still get it on older leaves (not a lot but it's there) and see it starting on my glass every week or so. 

Too high light or too long photo period can cause issues too. I had it MUCH worse when I was at 4x54w T5 HO lighting over my 72 gal going 10 hours/day. A lot of my Hygro leaves nearer the surface were getting it really badly. I cut back to 3x54W and 8 hours of lighting and I'm now perhaps only 3% of GSA to what I had before, but my plants are still growing just fine with less wattage and shorter lighting periods. If you light wattage is really high consider cutting back some, and if your photo period is over 8 hours considered dropping too. Try that for a few weeks and see what happens.

More here at this really good algae guide (scroll to GSA):

http://www.theplantedtank.co.uk/algae.htm


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## Hoppy

Ultimately, all algae is caused by "too much" light intensity for too many hours per day. It's also true that too vigorous plant growth is caused by the same thing.

Algae in planted aquariums seems to be started either by small surges of ammonia in the water or by unstable CO2 concentration in the water. But, once started, it is the light that drives algae growth.


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## Characins

The tank is in my siggy.

2x39w T5, 9.5 hours per day , 46g, DIY CO2 around 20-30ppm.

I haven't been dosing N+P, but I'll start as soon as I can find the time to drive to Big Als.


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## rich815

Ah! In your siggy..... :thumbsup:

What's a siggy? :confused1:


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## Characins

rich815 said:


> Ah! In your siggy..... :thumbsup:
> 
> What's a siggy? :confused1:


Signature.

Its the thing below my posts that has the link in it.


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## rich815

Characins said:


> Signature.
> 
> Its the thing below my posts that has the link in it.


Doh! Right. My stupid. For some reason I immediately thought you were referring to the room you had it in, and I could not think of a room that would be called a "siggy". :icon_roll


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## fishboy87

Back to the algae. . .

it can be caused by low phosphate but can still be an issue if photoperiod is too long as mentioned above. You can stop it/reduce it parameter-wise by reducing photoperiod and increasing phosphate. When it's on glass, I would recommend a nerite snail. . .really great for the stuff. I put 3 in my 29 and there's barely any at all any more. If it's on leaves (usually it grows on older, slower-growing leaves like ferns and anubias) get amano shrimp. I got 15 recently for the same tank for the spots the nerites couldn't get and I already see a difference after about 1/2 a week! It can be considered hard to get rid of but you just have to keep phosphate up to where it can't grow and try having a cleaning crew that consists of either nerites or amanos or both.


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