# Green water is back !



## Iceterran (Jun 15, 2007)

I had a green water outbreak a few weeks ago, and a few days w/o lights seemed to fix it. But now I just got back (I was away for 2 days) and its so green i can hardly see the fish. Whats causing this? and what can I do to prevent it permanently?

75G
15G sump
4X 65w PC 12:00 AM- 12:00 PM
Co2 is on the same timer, drop checker stays nice and green.

help!


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## MatPat (Mar 22, 2004)

What substrate are you using? Any root tabs or other fertilizer additions in your substrate? How are you fertilizing the tank and how long has it been set up?

I am guaranteed to get a case of green water any time I uproot a large amount of plants (or a large Crypt) in my 75g and do not do a water change. In my opinion, green water is caused by a release of ammonium from the substrate in combination with high light levels.

Given your light levels 8-10 hours should enough for your tank. Take a look at the plants in your tank around the 8 hour period. Are any of the leaves pointing straight up, similar to how they look in the morning when the lights first come on? If so, those plants have received enough light for the day. I know my L. aromatica and several other plants "close up" after about 8-9 hours of light. I have less than 3wpg on my 75g tank with about half of that wattage coming from less intense T-8 tubes. Light intensity and duration may be a key in the trigger of GW for your tank.


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## Brainman (Nov 13, 2006)

Iceterran said:


> I had a green water outbreak a few weeks ago, and a few days w/o lights seemed to fix it. But now I just got back (I was away for 2 days) and its so green i can hardly see the fish. Whats causing this? *and what can I do to prevent it permanently?
> *
> 75G
> 15G sump
> ...


Buy UV-C sterilizer, and no more green water for you


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## MatPat (Mar 22, 2004)

Brainman said:


> Buy UV-C sterilizer, and no more green water for you


UV, Diatom Filtration, or blackouts will clear up the problem but not solve it. To keep it from coming back you will need to either identify the cause, normally the release of ammonium from the substrate.


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## Iceterran (Jun 15, 2007)

The substrate I'm using is pool filter sand, 50lbs of it. And come to think of it, I recently stirred up the sand a lot by uprooting and moving a lot of plants around, could this cause an ammonia spike? The Fert system I use is the one described to me by Curtis, or Lyretail ( 50% h20 change week, and dose 50% of the water) Now heres a semi- related question: When I'm doing my water changes, I know I'm not supposed to Vac the substrate, but should I glide over it to remove poop that is sitting on top? Please LMK


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## MatPat (Mar 22, 2004)

Stirring up the sand can and usually does release ammonium. This is probably the cause of your Green Water depending on how much stirring you did.

I always hover the substrate to remove fish waste when I do a water change.


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## ItsDubC (Jan 12, 2008)

The presence of green algae could also indicate an excess of iron in the water column in a form usable by algae. Light creates more usable iron in the water column through photoreduction, which is why the blackout worked previously. 

The fact that you uprooted and moved many of the plants could have introduced excess iron into the water column.

In any case, a long-term solution might simply be to introduce more fast-growing plants to outcompete the algae. For now, you could do a water change, add floating plants, and/or break up your lighting schedule (ie 4hrs on, 1hr off, 4hrs on, 1 hr off, 2hrs on).


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## houseofcards (Feb 16, 2005)

You can search forever trying to find the reasons. Some tanks don't balance well due to filtration, bio-load and plant mass. Just get yourself a UV and you'll never have to worry about GW again. You'll also be able to play with the setup more and not have to worry.


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## tkos (Oct 30, 2006)

I my case it has always been java moss that caused green water. I let the java moss grow nice and huge and then as I trim it, it releases a ton of decaying material. This includes fish waste, food, and probably decayed lower levels of java moss. A thorough vacuum and a big water change have usually helped. I keep my java moss smaller now and have had no issues.


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## MatPat (Mar 22, 2004)

The blackout works because it doesn't allow the green water to produce food (photosynthesis). I've never had iron cause an outbreak of algae in a tank at least to my knowledge and I have dosed generous amounts of iron in the past and still do.

The addition of more plants is always a plus in the fight against algae. More plants means more mass to take up ammonia/ammonium. Try adding some ammonium nitrate to your tank and see if you don't get a green water bloom or other types of algae. Or, as you have already found out, stir up the substrate and release ammonia/ammonium into the water column.

Tkos, it was not the Java Moss that caused the algae but the decaying plant matter and food, again, probably a release of ammonia/ammonium into the water column. A simple water change anytime you do a big trim or a major substrate disturbance will help tremendously in the fight against algae. If you can't do a water change after a trim or uproot, use a diatom filter or purchase a UV sterilizer. These two items will remove the green water but a water change is pretty much free


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