# Help needed for green water/algae



## xpirtdesign (Dec 5, 2008)

I have a pressurized co2 tank and im dosing dry fertz per instructions on chucks calculator. I have about 4wpg on a 37 gallon tank. Its heavily planted and i have some mollies, tetras, and some shrimp.

I have my lights running about 7.5 hours a day, and my ph tester shows green after a couple of hours of the co2 being on. the co2 turns on about an hour before the lights do. I do 50% water changes every week.

My problem is green water as well as an green colored algae film growing on the glass. There is almost no algae on plants though.

I tried a black out for 3 or 4 days and that cleared up the water and glass completely, but about a week later it started growing back slowly. The water isnt extremely green, nor is the algae on the glass but its annoying and seems to be growing very slowly. 

My plants are growing very well, and I was dosing excel for a month or so but that wasnt doing much.

Any suggestions? I know something is probably out of balance...but i have no idea what. The only testing kit i have is a liquid PH tester and I have no money for any other equipment at the moment.

Thanks in advance.


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## Seattle_Aquarist (Mar 7, 2008)

Hi xpirtdesign,

I have a 45 tall with a DIY 96 watt CF fixture and had a little bout of green water shortly after the last tear down and restart. I dose with Excel (2 times normal daily dose). I cut my light period down from 8 hours to 5 hours and the problem cleared up after a week or so. Is this a new tank or has it recently been cleaned and restarted?


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## xpirtdesign (Dec 5, 2008)

its a couple months old so its fairly new. if i drop down the lighting time, should i slowly increase it back up or just leave it? if i cut down the light, wouldnt that take away from plant growth?


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## dj2606 (Oct 15, 2008)

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

My $.02 is go to your LFS and bring some water from your tank. Ask them test do a complete test. Most LFS do these tests for free.

Next instead of cutting your lighting down to 5hrs. Reduce the amount of light. For example, in your 8 hour photo period maybe have 4 hours with only 2 lights running. Then 2 hrs with all 4 lights running. Finally, the last 2 hrs cut back down to 2 lights again.

Also:
What type of filtration do you have.
Do you have any other source of water movement (powerheads)?
Heavily planted with what?


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## chagovatoloco (Nov 17, 2007)

Going to the local fish store and checking you water will just be chasing a dragon. I have some very good fish stores in my area, even some that are supposed to be plant experts and they are no help with a high tech aquarium. When I had this issue I went to a six hour photo period and in a few weeks every thing cleared. Give it time and only change things one at a time, every few weeks or so. Remember that it is never too much of anythings that causes algae but not enough.


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## dj2606 (Oct 15, 2008)

Well going to get the water tested will show if anything is out of the ordinary. Only testing the PH doesn't give the whole story. 

Telling us what the water parameters will help diagnose the issue so the problem doesn't keep reoccurring.


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## chagovatoloco (Nov 17, 2007)

I have seen small ammonia spikes cause this algae, usually due to a disturbance in the biological filter. Some thing like cleaning the filter with tap water will kill all of the beneficial bacteria. This causes a small ammonia spike in the tank and the algae takes action before the plants can adjust and start to take in the ammonia. The spike is not enough to affect the fish or plant growth but it will cause this algae. When thing get reestablished this will fade and go away.


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## Zapins (Jul 28, 2004)

I agree, ammonia spikes and intense lighting are green water triggers. 

The best treatment, is as many people have already mentioned, to reduce lighting duration and intensity until it clears up and then you can start increasing it again. At 4 WPG you are walking a fine line. You are driving your plants to their limit, so any small mistake or nutrient imbalance will be amplified and you will get algae very easily.

The plants will be fine with 6 or 7 hours of 2-3 WPG.

Don't use blackouts as an algae treatment. Blackouts are very harmful for plants, especially high light plants like HC and red plants. The "growth" that people usually notice during the blackout is really just preexisting cells inflating with water and stretching out towards the light. It isn't real growth, and it seriously depletes the plant's stores of sugars, making them less fit to compete against algae.

Reducing the light simply takes away the blooming trigger for green water algae, but keeps the plants satisfied with enough light. The amount of sugar they will make during 6 or 7 hours at half intensity won't be nearly as much as at 4, but it is far better to allow them a period of light so they can grow than remove it from them entirely.


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