What antibiotic type and dose to get rid of cyanobacteria?

[Rozski]

Have had it in my big tank for quite a few weeks now, and getting sick of it. When it first cropped up (a smidge in the floating plants I had) I scooped it out and blacked out my tank for 3 days, but it came back. Don't want to black out again as fish came out other side of blackout looking very pale and sad (and minus one young danio, which must have wedged itself somewhere, who knows)

Wondering what type of antibiotics, dose, how to etc I need to know to treat the tank.

Hopefully can pick them up easily enough (doing prac work at vet clinics lol)

In tank are angels, neons, danios, bristlenose, blue ram - will they be ok?

TIA

[Ira]

Erythromycin. Can't remember the dosage.

[jn]

Use the search at the top of the page... (Ignore the comment that says the search function is disbaled.. the google one works fine)

[tHEcONCH]

Metro also works well, but anything that kills cyano also kills your filter

[evilknieval69]

I've use erythomycin many a time and i have never had it kill a filter. Im pretty sure heaps of others here have used it without killing the filters either. Interesting that you say it does.

[tHEcONCH]

It might not kill it, but it definitely seems to put a dent in it - then again, it could be that the filter is trying to digest a huge amouunt of dead cyano - maybe that causes a bit of a Nitrite spike? Anyhoo, if people are using erythromycin with good results then that sounds like the way to go.

[Caryl]

I have the dosage at home so will check it tonight when I get home from work.

[alanmin4304]

The last time I used it the filter was killed off and so were the fish with the resulting spike. I have used it before at the same dose rate without problems but it is something to be aware of. By tha time I moved the fish to another tank the damage had been done and they died over the next couple of weeks. Antibiotics are designed to kill bacteria. If you only use antibiotics and don't correct the imbalance that is causing the problem you will get it back again.

[Rozski]

Well what can I change then? Tank is run just the same as my smaller one, which I don't have a cyano problem in.

Low light, but getting better lights for christmas to make my plants happy. Though cyano likes light, so I don't know if increasing light will help...

Rainwater used (as in other tank), standard pH, nitrates etc

[Discusguru]

I use 1 tab per 100ltrs water and they never come back.

ron

[Rozski]

Thanks ron,

Do you know how much is in a tab though??

Tho I can wait patiently for Caryl to post again tonight 8)

Coz otherwise knowing my luck, I will go, "hey, can I have a tab of erythromycin?", and the vet will say "in 50mg or 100mg?"

[jn]

What are your nitrates at? and if you don't have a phosphate test kit maybe the LFS can test that for you?

I had it pretty bad in a small tank. Nitrates were virtually nil and I was probably generous with feeding.

I put my fish into a holding bin. Emptied the tank, cleaned glass,scooped out the gravel (throwing away the top layer that was badly covered with it, sterilised it (bleach and very hot water, scrubbing to remove anything still attached) rinsed very well, sterilised plants in potassium permanganate, left the filter as it was. Worked as quickly as I could so the filter didn't suffer too much.

Then put it all back together, let it settle overnight before putting the fish back. I added a few fish after that and decreased my feeding. I also bought some nitrate fertiliser to use in case my nitrates ever dropped very low again but haven't had to use it.

Its never come back. This probably isnt practical if you have alot of fish or a big tank though I had a 40L tank and about 9 small fish !!

[Rozski]

Nitrates were normal last time I checked (a wee while I have to admit, I get slack when everytime I check things are stable, plus had exams etc) Not back to flat till this weekend, so will check everything then.

Like I said tho, had a tiny smidge, took it right out the tank, blacked out etc, and it just grew back. If it grew back from nothing, I dont think I could clean all my plants and driftwood well enough now to get rid of it? Big java fern etc, and don't want to damage plants (they already endured a shift a week and a half ago)

Will get store to check phosphate levels then :-)

[Caryl]

My pills were 400mg each. It has been suggested 400mg/100L. Someone else said 250mg/100L. I seem to remember using 4 pills in my 280L tank which was probably overkill but I didn’t know the dosage at that point and it certainly worked without harming the filters or fish.

I dissolved them in a cup of water first as they have a white coating which takes ages to dissolve.

I siphoned out the dead cyano quickly (it starts to die within 24hrs) then repeated the dose 3 days later.

Someone else asked and I suggested 2 pills for his 280L tank with a repeat, as above, 3 days later and he reported back that it worked well.

[evilknieval69]

I've always used 400mg/100L and it works first time, every time. You do however, as has been said, need to fix the cause.

[alanmin4304]

Again, 400mg/100litres but fix the cause (usually too much PO4 low NO3)

[Rozski]

OK, thanks everyone. Will check my nitrate levels, and hopefully be able to get someone to check my phosphate levels and see if something is going wrong there.

If there is something clearly wrong that I can fix, do I still needs the ABs or is correcting the imbalance enough to kill the cyano?

[reef]

try vodka, 1ml/100l should remove cyno.

[alanmin4304]

I have succssfully used H2O2 before but I can't remember the dose---someone else may.

[evilknieval69]

Reef, i don't think dosing vodka works in a freshwater tank. Correct me if i'm wrong