# Adding phosphate to clear greenspot algae



## colio (Dec 8, 2012)

I have a growing amount of greenspot algae in my tank, which I have read is often caused by a lack of phosphates. So adding phosphates help aleviate the problem. On the other hand, most people are more concerned with removing phosphates from their aquariums. 

I was considering trying to add phosphate, but I am not sure what would be a good source, or where to get it. Is this a good idea? I don't have, and probably can't get in the short term, a phosphate test kit, though maybe I really need one before I start messing around with this. 

I'm happy to hear any other thoughts on reducing the spread of green spot. 

details:
35 gallon, heavily stocked, really densly planted
nitrate around 25 ppm, 0 amonia and nitrate, ph 7.5
dosing low-medium doses of iron-potassium.


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## pyrrolin (Jan 11, 2012)

Interesting idea, I'll be watching


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## balutpenoy2oy (Feb 17, 2011)

too much light is also a cause of GSA specially direct sunlight. IME..


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## LTPGuy (Aug 8, 2012)

I find this web site quite useful and I hope that it may help you.

With regard to GSA here is an excerpt:


> Green Spot Algae, GSA http://www.theplantedtank.co.uk/algae/gsa1.jpghttp://www.theplantedtank.co.uk/algae/gsa2.jpg *Description* Forms hard green circular spots on the glass and slow growing plant leaves. *Cause* With Estimative Index low phosphate levels often bring on a GSA outbreak. Also Low CO2 and poor water flow. Too long a lighting period doesn't help. *Removal* If dosing Estimative Index increase phosphate levels by adding monobasic potassium phosphate or fleet enema solution. Aim for a level of 2 to 3ppm. Check CO2 levels and water flow. Can be scraped off the glass using a razor blade or a good magnetic glass scraper. Between 9 and 10 hours is plenty of lighting time for the plants. If it is more then reducing it may help.
> If dosing a lean dosing method like PMDD or PPS-Pro then modifying the NO3 to PO4 ratio normally helps. A bit of trial and error may be required.


from this website.

Good luck.


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## Fishfur (Mar 4, 2012)

I know I had an outbreak of green spot when my aquarium was fairly new, close to a year ago now, but it did not last too long. Even though the tank is in a south facing window, it has not had any more green spot since that first outbreak. I scraped it off, and it really didn't regrow very much, and eventually just disappeared. The majority of the algae I see now grows on the outflow of the AC filter.. and I scrape that off when I clean the filter. I also covered the filter with mylar to slow down algae growth in side and it has worked pretty well, keeping it almost all gone, other than on the outflow lip, which is exposed to the lighting.

The second tank, same window but on the other side of the air conditioner, has been running about six months now. It grows a bit of green spot now and then, but only on the back glass, closest to the window. I scrape it off sometimes. It's not terribly thick, but I think it will eventually go away on it's own like it did in the first tank. Only time will tell if this is the case. If not, I'll cover the back of this tank with mylar too. More of a nuisance is a patch or two of hair algae that persists in returning. I'm thinking I'll have to dose it with peroxide or something as it appears that just pulling it out is not going to work.

I don't dose a lot of ferts.. though I plan to change that, as I'd like to see lusher growth. I'm also starting a slightly higher tech tank just to grow a few plants faster, and it will be interesting to see what algae issues crop up with that. But I suppose there could be a phosphate shortage in the second tank that's fuelling the green spot. But unlike the hair algae, unless the spots got very thick or showed up on the front and sides, it doesn't worry me overmuch.


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## colio (Dec 8, 2012)

I am most certainly leaving the light on to long. But I want to see my fishes at night. I get a bit of sun on the tank in the morning to. Relocating is not an option. 

It has been spreading for a while now. I hoped it would slow on its own, but instead it is getting a bit of an issue. I was away, then sick, so there is some tank neglect, but I have been having trouble removing it from my front glass panel. I am hoping I can do something to arrest the continues growth of th stuff before I can't see my tank any more.


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## Fishfur (Mar 4, 2012)

Best of luck. Scraping it off was not a big chore and it seemed to slow it down a lot for me. I also cut down the time I left the lights on.. when I started I had them on 12 hours, now it's about 8 hours. But my current lighting is brighter than what I started with too. 

Both tanks get sun, but the newer one gets more of it, which I assume is helping fuel the hair algae and probably the green spot too. Likely I'll end up covering it with mylar film. I've tried leaving the lights off for a few days at a time, and it's slowed down the hair algae, but not stopped it entirely.

The mylar I have is super thin, similar to what you get on candy bars but it came on a roll. It does a very good job of reducing the light that comes in from the window, whether it's on the tank or on the window. I'd venture a guess that the sunlight is reduced by at least 50%, quite possibly more than that. 

You can see through it, but lines will be distorted, since it is very cheap film. I think it was intended for Halloween costumes originally, but it works very well as a solar block. If put on a window, the light coming in looks very dim compared to a window without the film. Certainly it helps to cut solar gain in hot weather, though I don't much care for how it looks on a window from the outside.


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## pyrrolin (Jan 11, 2012)

I paint the back of my tanks black to hide cords and stuff, it might also help block out the extra sunlight.


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