Help with stubborn Cyanobacteria

[Kadina]

I am having a severe problem with cyanobacteria in my 3 gallon betta tank. The tank is fully cycled and has been running for 18 months. It has a 6w T5 light that is on for 10 hours a day. I have 3 java ferns and a sand substrate in the tank. I change 1/3 of the water once or twice a week, depending on how busy I am at work where the tank resides.

The past 3 months I have been fighting a losing battle with cyanobacteria. Here are the things I have tried so far:

Complete blackout for 7 days
Increase photo period to 14 hours (from Dave's primer)
Siphoning out all the gunk on every water change.
Complete substrate replacement.


Nothing has worked and the cyanobacteria just keeps coming back and covering everything in the tank. Any other suggestions? I have been reluctant to try it, but maybe I shuld get some antibiotics? I am really close to tearing the tank down entirely because it is so disgusting.

[robflanker]

Try getting a syringe and shooting it with hydrogen peroxide. Use a max of 3mL per gallon.
Leave it for an hour without any current in the tank (no filter, no powerhead) and then turn everything back on. Leave the lights on tho.

Worked for my algae and thanks to PostalPenguin for that advice

[MonkeyPox]

Try Phos-guard or a similar product

[rich311k]

Antibiotics - eurythromicyn or Maracyn 2 will kill it. It may kill you bio filter as well so be careful. If it does not work the first time try a second course. If the second course does not work the you have antibiotic resistant cyano and you will need to go to another method.

[Alfcea]

Try getting a syringe and shooting it with hydrogen peroxide. Use a max of 3mL per gallon.
Leave it for an hour without any current in the tank (no filter, no powerhead) and then turn everything back on. Leave the lights on tho.

Worked for my algae and thanks to PostalPenguin for that advice

I don't think Hydrogen peroxide works on cyanobacteria... It is mainly used for hair (or bba) algae...

To treat stubborn cyanobacteria, you could use erythromicine or another antibiotic... but make sure your filter is off, so you don't kill your biofilter too!

[Algenco]

Antibiotics - eurythromicyn or Maracyn 2 will kill it. It may kill you bio filter as well so be careful. If it does not work the first time try a second course. If the second course does not work the you have antibiotic resistant cyano and you will need to go to another method.


Worked for me

[dmagerl]

I tell ya, UltraLife Blue Green Algae Remover works like a charm. Cyano was taking over my tank and with 1 dose, it's never come back. It's not an antibiotic so it doesnt harm the filter.

[PostalPenguin]

I don't think Hydrogen peroxide works on cyanobacteria... It is mainly used for hair (or bba) algae...

To treat stubborn cyanobacteria, you could use erythromicine or another antibiotic... but make sure your filter is off, so you don't kill your biofilter too!

I think it would work. Peroxide is a potent disinfectant, its used to treat cuts and scrapes on humans so it should impact the cyanobacteria. I have never tried it on cyano so I cannot say for sure but I would assume it works.

I have found peroxide to be one of the best aquarium treatments, it has killed every type of algae I have come across(BBA, green dust, green spot, hair, staghorn) without damaging a single plant or killing a fish.

Try peroxide Kadina and if it works, let us know.

If it doesn't erythromycin will wipe it out. But make sure to monitor your ammonia and nitrites since it may harm your filter.

And here is a great site for algae: http://www.guitarfish.org/algae It prescribes peroxide treatment to treat cyanobacteria.

[bushwhacker]

i tried everything in my 55 to kill bga. had to get maracyn (erithromicin) did 1/2 doses for about 5 days a week later it showed up again i did one more dose and its not come back ... it did kill my cycle and i lost some fish but the tanks been stable since