Puzzling Algae Behavior

Woodsman27

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I have a 50 gallon acrylic with 9 black skirt tetras and no live plants and I'm having an algae issue. The fake pirate's ship I have in there was from an older tank I had setup prior to this one. There is a slimy layer of green algae on both pieces but that's not the puzzling part.... when I wake up in the morning and turn my light on the water is green and murky, but when I turn the light off at night the water is crystal clear! I dont understand, I thought algae thrives on light? Shouldn't it be green water at the end of the day? I failed to mention my tank is not quite cycled yet, but it's close. Any tips on getting rid of this crud? Does hydrogen peroxide really work/harm fish? Any help would be greatly appreciated.
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Woodsman.
 

Momgoose56

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I have a 50 gallon acrylic with 9 black skirt tetras and no live plants and I'm having an algae issue. The fake pirate's ship I have in there was from an older tank I had setup prior to this one. There is a slimy layer of green algae on both pieces but that's not the puzzling part.... when I wake up in the morning and turn my light on the water is green and murky, but when I turn the light off at night the water is crystal clear! I dont understand, I thought algae thrives on light? Shouldn't it be green water at the end of the day? I failed to mention my tank is not quite cycled yet, but it's close. Any tips on getting rid of this crud? Does hydrogen peroxide really work/harm fish? Any help would be greatly appreciated.
Thanks,
Woodsman.
What are your water params? Might be time for a near-end of cycle water change...
 
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Woodsman27

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Thanks for your response, my levels are: ammonia 0ppm, nitrites~2ppm, and nitrates are ~15ppm.

I kept the light on for a little longer last night, and when I woke up it wasn't as bad... I do have a blue light that stays on all night, maybe that's what's causing it?
 

Momgoose56

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Thanks for your response, my levels are: ammonia 0ppm, nitrites~2ppm, and nitrates are ~15ppm.

I kept the light on for a little longer last night, and when I woke up it wasn't as bad... I do have a blue light that stays on all night, maybe that's what's causing it?
Your nitrites are way too high at 2ppm. Are you using Prime? I'd recommend doing at least a 75% water change and redose with Prime. The high nitrites may be contributing to your algae problem. I wouldn't think blue light would increase algae but I'm not a spectrum specialist. I guess it would depend on the kind of blue light. This might be a great question to post in a new thread in the lighting forum!
 

kallililly1973

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The nitrites are too high and i would turn the blue light off at night that would definitely cause an algae issue. Whenever your Ammonia or nitrites go close to or over 1 ppm you should be doing a WC and declorinating with Prime to lock the dangerous levels upto 1ppm for 24-48 hours.
 

Momgoose56

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The nitrites are too high and i would turn the blue light off at night that would definitely cause an algae issue. Whenever your Ammonia or nitrites go close to or over 1 ppm you should be doing a WC and declorinating with Prime to lock the dangerous levels upto 1ppm for 24-48 hours.
I know blue and red light can be used for photosynthesis but wasn't sure all blue light can? That's why you never see plants grown under green lights- all green light has the wrong wavelength... So, @Woodsman27, if you have to have a nightlight on in your tank at night, green would probably be a better choice lol!
 
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Woodsman27

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I agree that the nitrite are high, no doubt about that... I have been doing a 50% pwc every day for a while now :dead: just havent done one yet today!

@Momgoose56 I suppose I dont absolutely need a light on at night I just think it looks cool lol.

So how do i get rid of the algae? I read that adding hydrogen peroxide works. Is it safe though?
 

kallililly1973

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I agree that the nitrite are high, no doubt about that... I have been doing a 50% pwc every day for a while now :dead: just havent done one yet today!

@Momgoose56 I suppose I dont absolutely need a light on at night I just think it looks cool lol.

So how do i get rid of the algae? I read that adding hydrogen peroxide works. Is it safe though?
Cutting your lights on schedule can usually get rid of a lot of algae, overfeeding will cause algae and higher nitrites as well so limit both of those for a week and see if you notice any difference. Manual removal is also usually a great option for algae if its on your glass just take an old used up gift card before your next WC scrape the glass and suck up a good 60-70% of your water.
 

kallililly1973

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I know blue and red light can be used for photosynthesis but wasn't sure all blue light can? That's why you never see plants grown under green lights- all green light has the wrong wavelength... So, @Woodsman27, if you have to have a nightlight on in your tank at night, green would probably be a better choice lol!
When i first got my Finnex planted 24/7 light i was leaving it on the 24/7 mode and from 12-3 it would be just moonlight rather than total darkness which i believe the new model Finnex offers and was getting algae so i switched to just the highest setting for 8 hours and have since been close to algae free aside from some stuff the inhabitants will take care of. Just my experience . Fish need total darkness for their sleep time just like we do
 
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