# Overrun by algae



## George02 (Jan 11, 2007)

Hello,

I have 2 planted tanks: 10 gallon and 20 gallon. I use 10 gallon as a fry tank for guppies. Both tanks are overrun by algae, especially the 20 gallon.

10 gallon tank has a sponge filter in it, about 20 guppy fry and about 10 plants plus a nice chunk of java moss. All plants are growing very nicely especially java fern and java moss. No CO2 in this tank, I add Flourish Excel. Pretty much everything in this tank is getting covered by green spots. I try to remove as much as I can manually, but it just keeps coming back.

20 gallon tank is a real mess. This tank is completely overrun by green water. It's so bad that I can't see into the tank at all. Also, this tank has green spots on the glass as well as hair algae. This tank is pretty heavily planted. It contains 12 guppies, 1 pleco, 1 SAE and who knows how many guppy fry. I use a Penguin 150 power filter for this tank. CO2 is supplied by Haegen CO2 system as well as Flourish Excel, I'm also in the process of making DIY yest CO2 system.
Again, all plants are growing really well. I do 20% WC once a week, and have been changing filter media once every 2 weeks trying to filter it out.

For both tanks I use Seachem ferts and their scheduling system.
I am at a complete loss what to do here. I've read posts here and it seems like the best way to go is to get a UV sterilizer. Is that right? If so which one would you suggest that could be used on both tanks.

Please help.


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## Bert H (Mar 2, 2004)

What is your lighting and photoperiod on these tanks? How long have they been set up? 

From what you describe, I would say you have an imbalance and/or are lacking in certain nutrients needed by the plants. The first thing is to try to figure out what's out of whack. Then you can take the steps to correct it. Typically, you would manually clean/remove as much as possible, do a major water change and make sure your ferts, CO2 (or Excel), and lighting/photoperiod are all in order.


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## George02 (Jan 11, 2007)

Bert,

I apologize, I should have included my lighting info in the original post. 20 gallon tank I have 65watt light for 9 hours a day. 10 gallon tank is 30 watt light for 11 hours a day. I leave lights on longer in the 10 gallon because of fry.
20 gallon tank has been setup for about 8 months and 10 gallon for about 3 months.

As far as ferts go, I've been following Seachem schedule form their website since I'm using their ferts. I'm using their entire line. Is this not a very good method to use? Here is the link to their dosing schedule http://www.seachem.com/products/planted.html you'd have to click on "dosing schedule" link on the right.


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## Bert H (Mar 2, 2004)

George, I would suggest that for the time being, drop your photoperiod to 8 hours on both tanks. My gut reaction is to say you don't have enough ferts for your plants/tank/conditions. Make sure you're dosing Excel daily, rather than every other day. Lack of CO2 and 65W on a 20gal can be problematic. Green spot algae is commonly seen when your phosphates are too low. 

In regards the green water, blackouts work well here. Do a search for details, I think a 3-4 day total blackout is quite effective against this. Then do a major water change, and dose back to normal levels (around 15ppm NO3, and 2-3ppm PO4).

You might want to post on the Seachem sponsor forum and ask how their dosing schedule relates to your weekly water changes. In other words, the schedule may be maximized for no water changes, or for 50% water changes, etc. This can give you an indication of whether you're over or (more likely, imo) under dosing any particular nutrient.


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## George02 (Jan 11, 2007)

Bert,

I'll cut the light period to 8 hours like you suggest. I do dose Excel every day, 4-5ml in 20 gallon and 2ml in 10 gallon.
I didn't test phosphate levels in the 10 gallon, but they are at around 5ppm in 20 gallon tank and Nitrates are at 30ppm in 20 gallon.
I'll follow up on your advice to post on Seachem sponsor forum.


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## George02 (Jan 11, 2007)

Well, I provided wrong numbers for phosphate and Nitrate for the 20 gallon.
Phosphate is over 10ppm and Nitrate is pretty much at 0.

The tank is cycled and I do add Nitrogen as a fertilizer. So maybe I should be adding more.
I also was told at a LFS that green water is probably being fed by phosphate, which I have too much of in this tank. Is that true? Should I stop adding phosphate?

Thanks


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## Bert H (Mar 2, 2004)

> Phosphate is over 10ppm and Nitrate is pretty much at 0.


I daresay, you found the reason for your algae issues. It is n't so much the high PO4, but the lack of NO3. Balance is the key in maintaining tanks algae free. Giving the plants all they need is a must.

Do major cleaning, gravel vac, etc, removing as much algae as possible. Do a major water change. Make sure your test kits are accurate, and then get your NO3 around 15ppm, your PO4 around 3ppm.


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## George02 (Jan 11, 2007)

I guess I really don't understand this, but if Nitrate comes up as 0 (which it did at the end of the day, a couple hours before the lights turned off), doesn't it mean that the plants consume all off it? Which means algae shouldn't have any nutrients for itself, which should slow algae down. That's why too much phosphate feeding the algae made sense.


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## Bert H (Mar 2, 2004)

> ...Which means algae shouldn't have any nutrients for itself,...


Algae exist in the microscopic realm. They can thrive in the parts per billion, whereas plants need parts per million. You will NEVER be able to starve algae. The idea, as crazy as it may sound to you, is NOT to starve alage (since it can't be done), but to provide all the plants need in a steady amount. When you run out of a needed plant nutrient, the plant's growth will come to a halt. YOU DO NOT WANT THAT TO HAPPEN! When the plants stop growing, the algae will. Having an excess of nutrients (within reason) will not cause algae to grow, but having an imbalance in your nutrients will.

Run some searches here for algae and algae control - there's a lot of stuff out there. This link, though long, can be quite enlightning, imo.

Good luck.


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## George02 (Jan 11, 2007)

Bert H

you were absolutely right. I increased the dosage of nitrate and vuala, within days, green water is almost gone. The water is almost crystal clear.

Thanks a lot.


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