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Should I black out or reduce lighting?

wtusa17

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I am currently trying to treat Cyanobacteria in my heavily planted tank. I just did a 50% wc and tried to remove as much of it as I could. Now should I black out the tank for 3 days or should I just reduce the lighting period? The light is on for 7 hours a day.
 

Byron

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Blackouts do not work to remove cyanobacteria unless you also deal with the organics. The blackout, just as my reducing the tank lighting photoperiod by an hour, will help achieve the end goal, but it is not the answer to the problem.
 
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wtusa17

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Blackouts do not work to remove cyanobacteria unless you also deal with the organics. The blackout, just as my reducing the tank lighting photoperiod by an hour, will help achieve the end goal, but it is not the answer to the problem.
Ok so just reduce by an hour and then what?
 

Byron

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Ok so just reduce by an hour and then what?
I explained how to deal with this in the other thread. I appreciate it may not be the answer you want as it takes time to achieve the goal, but that is still how to deal with this problem.
 
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wtusa17

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I explained how to deal with this in the other thread. I appreciate it may not be the answer you want as it takes time to achieve the goal, but that is still how to deal with this problem.
What about co2?
 

Colin_T

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Cyanobacter bacteria (blue green algae) is a photosynthetic bacteria that can grow in bright conditions or in the dark. Reducing light does not fix the problem.

Do big daily water changes and gravel clean the substrate to physically remove the nutrients and the blue green algae.

Increase aeration and water movement around the tank.

If you have fluorescent globes above the tank, and they are more than 12 months old, look into replacing them with new globes that have a 6500K (K is for Kelvin) rating.

Reduce dry food and use more frozen (but defrosted) and live foods.
 
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wtusa17

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Im getting conflicting info here. Don’t know what I should do. One person is suggesting reducing light and the other says not to
 

I nEEd mEnTAl HeLP

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Do you have phosphates? I'm definitely no expert, but from my understanding, having a blackout does not solve the problem. Its just a temporary fix.
 
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wtusa17

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Do you have phosphates? I'm definitely no expert, but from my understanding, having a blackout does not solve the problem. Its just a temporary fix.
How do I test? The omega one color flakes is what I’m feeding and I read ingredients and didn’t see phosphates
 

Byron

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Im getting conflicting info here. Don’t know what I should do. One person is suggesting reducing light and the other says not to
If I am the person suggesting reducing light, you have not taken that in the context I presented it, which may be due to my not having explained it well. I reduced the photoperiod in my tank when I was dealing with cyano by an hour, but I did massive water changes and cleaning to rid the tank of organics. I also eliminated plant additives for a couple of weeks, on the same reasoning, that limiting or eliminating all factors is more likely to benefit the goal.

I had a 10g tank in a west-facing window as an experiment for a year. No filter, no light, just a heater. Lots of plants, and a group each of pygmy cories and chili rasboras, 12 or so each. I had to deal with cyano on the back glass. Obviously that was due to the light that was not controlled even with miniblinds. The organics in the tank fed it, and the light encouraged it. Once I moved the tank away from the window, the cyano disappeared. This doesn't mean a blackout would have solved it--if I had done a blackout, as soon as I ended the blackout the cyano would be right back. Reducing the photoperiod in combination with keeping organics under control worked.
 

Colin_T

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You have your light on for 7 hours a day. Reducing it by 1 hour per day is not going to do anything to Cyanobacteria, but less light will stress your plants a bit.

Blue green algae (bga) grows from excess nutrients. That is why it appears in lots of rivers and creeks nowadays. There is lots of nutrients in the waterways and Cyanobacteria love the nutrients. When the waterways are cleaned up and fertiliser run off is reduced, the blue green algae go away.

The same thing happens in the aquarium. Reduce the nutrients and increase aeration/ water movement, and the blue green algae won't do as well. Combine this with physically removing the sheets of bga and gravel cleaning any exposed areas of substrate, and you can get rid of it.
 
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