# Too much light?



## kilfrg7864 (Sep 22, 2009)

i have a 15 gallon with a little over 2wpg t8 bulbs sitting directly over the tank. 

My problem is ever since setting up the tank about 5 weeks ago i have had a horrible blue green algae problem. I am assuming this is caused by my photo period combined with the extra DIRECT(~3-4hrs) as well as INDIRECT(rest of the day) sunlight my tank gets throughout the day.

i was running the lights on a 5-4-5 period, and then reduced it to a 4-4-4 period. But yet the blue green algae still persists. Im afraid if i lower the photoperiod anymore i will start to hurt the plants.

Any suggestions on photo periods, or what to do about the sunlight/ artificial light to reduce this huge outbreak of blue green algae?


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## hornedtoad1 (Jun 24, 2011)

hi kilfrg,
i set up a 5-gal nano dry start that developed bga a month and a half into the setup, and dosing with erythromycin took care of the problem. the dry start was on a straight 14-hour light cycle; don't know whether or not that brought on the bga. it's been submerged now for about a month with no recurrence. it has a 13w cfl, 5-4-5 hour cycle; it doesn't get any direct sun, tho.
you might be able to leave the light off when your tank's getting direct sunlight.


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## nkambae (Nov 6, 2007)

I would say, yes, you have too much light for the nutrients available to the plants. I would cut the T8 photo period to 4-5 hours plus the direct sunlight per day. I would change your photo period and wait up to a month before changing anything else. If you change more than one parameter at a time you won't know which changes are effective or not.

In addition to the change in photo period, I would remove as much of the BGA as possible in conjunction with several large water changes over the course of a week. After that I would wait and see what happens with the reduced light.

You can also add a lot of floating plants if you are married to your current photo period. This can be a good way to cut back on the amount of light reaching your plants. Check out the algae guide here:

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

I found it to be helpful. Good luck.

stu


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## kilfrg7864 (Sep 22, 2009)

any ideas where i can find erythromyocin from?

I think i want to try to do the antibiotic +reduce the photo period to about 5 hours and see how it goes


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## londonloco (Sep 25, 2005)

I have used this twice, worked like a charm:

http://www.amazon.com/Blue-Green-Algae-Remover-gallons/dp/B002DVPLHQ


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## hornedtoad1 (Jun 24, 2011)

also thatpetplace.com has it.
http://www.thatpetplace.com/pet/pro...=erythromycin&searchParams.size=10#resultBody


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## hornedtoad1 (Jun 24, 2011)

erythromycin is actually an antibiotic (bga isn't really an algae, it's a bacteria). it's non-prescription and should be available at your lfs.


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## musrusticus (Aug 21, 2008)

I've had success using a 3 day blackout period. None of the plants or fish were harmed (I had an HOB filter going throughout) and after the blackout the BGA was gone. It never came back more than a small spot here and there and I didn't have to dose with anything.


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## kilfrg7864 (Sep 22, 2009)

i dosed EM, and reduced the light period down to 5 hours a day.

Im not sure if its the reduced light, or lack of nutrients but a lot of my newer growth is coming out yellow. 

Is this due to the reduced amount of light??


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## wi_blue (Apr 5, 2005)

kilfrg7864, I wouldn't go below 8hrs a day on the lights. BGA from what I've read is a bactiria that feeds on excess nitrogen. The EM should take care of it. The lights shouldn't have any direct affect on it.


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## kilfrg7864 (Sep 22, 2009)

im not sure if you read my previous post, but my tank gets almost 3-4 hours of direct sunlight, and gets alot of in direct sunlight throughout the rest of the day.

Are you saying that the 8 hours should be 8 hours of artificial lights on top of the direct sunlight? I tired earlier to reduce my photoperiod to 8 hours before the EM treatment and the BGA was still growing like mad.


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## wi_blue (Apr 5, 2005)

Ouch! I did not catch the direct sun. Sorry. The light shouldn't be causing the BGA still, though may encourage other forms on algea. The 5hr light period should be a good start.


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## nkambae (Nov 6, 2007)

Erythromycin is effective in killing cyanobacteria but unless you remove the cause of the bga outbreak, it will be back. I would definitely leave the tank lights off during the day. Especially when it is getting direct sunlight. Perhaps you could just have the lights on in the evening when you are at home to enjoy the tank. 

There seems to be a link between low nitrogen and bga. What is your current bio load? Could you add another fish or three to add some more nitrogen to the system? Or you could give the tank a light dose of ferts whenever you do a water change. Good luck.


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## dawntwister (Sep 29, 2007)

kilfrg7864 said:


> i have a 15 gallon with a little over 2wpg t8 bulbs sitting directly over the tank. Photo period combined with the extra DIRECT(~3-4hrs) as well as INDIRECT(rest of the day) sunlight my tank gets throughout the day.


So you have 2 T8 bulbs over the tank? I only use 1 T8 18 watt over my 10 gallon tank. Also it is in a room with no indirect light. Definitely to much light.

How about a pic.


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## kilfrg7864 (Sep 22, 2009)

just an update, dosed EM. And it hasnt come back! 

i think it was caused by the BGA building up in my filter. even though i removed it from the tank itself and did a water change it would come back because of the filter. 

but i cleaned the whole filter and cleaned as much bga from the plants and its gone and hasnt come back! hopefully it wont come back either *crosses fingers*


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