Should I black out or reduce lighting?

[wtusa17]

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.

Ok I understand that a blackout is temporary so you are suggesting daily wc or? I thought you said you did 1 a week and if I did let’s say 2 a week would that help eliminate it?

 

[wtusa17]

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.

I have fluval stratum so I can’t clean the substrate. So basically it’s just letting the plants use up the nutrients on their own instead of adding extra nutrients that the Cyanobacteria can use?

 

[Colin_T]

Doing water changes and sucking out any gunk on the top of the substrate will dilute nutrients in the water, then leave the plants to use the nutrients in the substrate. And don't add other forms of nutrients (fertilisers) if you have slow growing plants.

 

[utahfish]

When had cynobacteria i did a total blackout. While cynobacteria has shown to be able to grow with out light it doesnt mean light wont make it grow. Blackout the tank it will decrease its growth rate, increase tank circulation and dissolved oxygen and turn down temp. Again while cynobacteria can grow in cooler temps warmer temps encourage growth. I did watee changes every day during the blackout as well and cleaned the filter, be sure to not kill beneficial bacteria while doing so.

 

[wtusa17]

When had cynobacteria i did a total blackout. While cynobacteria has shown to be able to grow with out light it doesnt mean light wont make it grow. Blackout the tank it will decrease its growth rate, increase tank circulation and dissolved oxygen and turn down temp. Again while cynobacteria can grow in cooler temps warmer temps encourage growth. I did watee changes every day during the blackout as well and cleaned the filter, be sure to not kill beneficial bacteria while doing so.

So are you suggesting a blackout? It’s heavily planted

 

[utahfish]

So are you suggesting a blackout? It’s heavily planted

Yup. The plants arent going to die in 3 days. My tank with cynobacteria was heavily planted as well. The plants may get a little grumpy but the cynobacteria is killing them anyway, as long as the roots are intact the plants will be fine and bounce back. I put a towel over my tank for 3 days, and did large water changes daily increased water flow turned down temp and didnt feed for 3 days. After those 3 days none of my fish or plants died or got sick, but the cynobacteria was gone or dead and needing to be removed. Good luck cynobac is the worst

 

[wtusa17]

Yup. The plants arent going to die in 3 days. My tank with cynobacteria was heavily planted as well. The plants may get a little grumpy but the cynobacteria is killing them anyway, as long as the roots are intact the plants will be fine and bounce back. I put a towel over my tank for 3 days, and did large water changes daily increased water flow turned down temp and didnt feed for 3 days. After those 3 days none of my fish or plants died or got sick, but the cynobacteria was gone or dead and needing to be removed. Good luck cynobac is the worst

Ok so it worked. I’m once again getting conflicting info. Don’t know what to do. How long did it take for the Cyanobacteria to totally disappear?

 

[Byron]

I don't think you are getting conflicting information. If you read what Colin has posted, and utahfish, and myself, you will see we are on the same page with respect to the basic underlying issue...reduce the organics. The blackout on its own is not going to work. It will (or should) reduce the cyano more rapidly, as will discontinuing plant additives, and not feeding the fish. Ensuring the organic level is drastically reduced will mean the cyano will not come back, always provided the biological system is in balance at the end of the "treatment."

One of the benefits of the method I used was that it allowed me to see quite clearly how effective my efforts were. It took three, maybe it was four weeks, to completely eradicate it--but by eradicate I mean it did not increase once I removed it. And as with algae, that is the goal, to ensure the cyano does not continue to increase/appear. Each week when I came to the water change I could clearly see that the cyano was minimal compared to the previous week, so I knew I was on the right track. If you do a blackout, at the end the idea is to have no cyano and that you can see...but you have no way of knowing whether you actually eliminated the cause or not. When I saw it being significantly less and less each time, I knew what I was doing was working. That aspect is up to you. But it is still the food--organics--that have to be lowered.

 

[utahfish]

Ok so it worked. I’m once again getting conflicting info. Don’t know what to do. How long did it take for the Cyanobacteria to totally disappear?

After the 3 days i didnt have any live cynobacteria just dark dead stuff floating around in water and on top of substrate, so i sucked all that out during the 3 days and after wards because it still contains spores. The 3 days worked for me for some it may not. I dont think there is an exact method to get rid of it, ive found the best way is to limit the things that help it grow for an extended time. While it can live without light, light helps it grow and it will thrive under high light. Limit nutrients decrease temp as bacteria thrives in warmer environments.
There really shouldnt be any conflicting info on this. The way to kill anything is to eliminate what helps it grow or live until its dead. Light and nutrients help cynobacteria grow, eliminate those for a long enough time and it dies.

 

[wtusa17]

After the 3 days i didnt have any live cynobacteria just dark dead stuff floating around in water and on top of substrate, so i sucked all that out during the 3 days and after wards because it still contains spores. The 3 days worked for me for some it may not. I dont think there is an exact method to get rid of it, ive found the best way is to limit the things that help it grow for an extended time. While it can live without light, light helps it grow and it will thrive under high light. Limit nutrients decrease temp as bacteria thrives in warmer environments.
There really shouldnt be any conflicting info on this. The way to kill anything is to eliminate what helps it grow or live until its dead. Light and nutrients help cynobacteria grow, eliminate those for a long enough time and it dies.

Ok I understand the basics now. I’m just confused on how y’all don’t think it’s conflicting? One person says it does 0 for treatment and someone says it worked for them. I’ll just let the plants do their thing and not add ferts then

 

[utahfish]

I don't think you are getting conflicting information. If you read what Colin has posted, and utahfish, and myself, you will see we are on the same page with respect to the basic underlying issue...reduce the organics. The blackout on its own is not going to work. It will (or should) reduce the cyano more rapidly, as will discontinuing plant additives, and not feeding the fish. Ensuring the organic level is drastically reduced will mean thee cyano will not come back, always provided the biological system is in balance at the end of the "treatment."

Exactly. Blackout without water changes wont do much because the bacteria will still feed on the organics, which is why water changes no feeding no fertilizing is important. Taking a comprehensive approach eliminates the most variables.

 

[utahfish]

Think of light as cynobacteria ice cream. I dont need ice cream to live, if i dont eat ice cream for 3 days im not going to die, but if i eat ice cream for 7 hours a day for 3 days im going to get fat. Light makes cynobacteria fat and while the absence of ice cream(light) wont kill it it will keep it from getting fat and contribute to its demise

 

[wtusa17]

Think of light as cynobacteria ice cream. I dont need ice cream to live, if i dont eat ice cream for 3 days im not going to die, but if i eat ice cream for 7 hours a day for 3 days im going to get fat. Light makes cynobacteria fat and while the absence of ice cream(light) wont kill it it will keep it from getting fat and contribute to its demise

Nice explanation. Should I just do water changes like every other day then? Also should I keep the light the same?

 

[utahfish]

Nice explanation. Should I just do water changes like every other day then? Also should I keep the light the same?

Id do water changes every day at least 75% and blackout for 3 days, take the ice cream away from that cynobacteria. And clean the filter. Theres always a lot of goo in filters.increase water flow decrease temp.