Uh oh! Blue Green algae! :(

[Fishies86]

OK, ive got Blue green algae again in my tank and need some advice on how to get rid of it. I had it about 4 months ago but it disappeared when I moved house and at the same time I stripped the whole tank down and replaced everything except the filter which I scrubbed to death

Its now just started to make a come back and I want to get rid of it before it really gets hold again. I've been trying to read up on it but got a lot of conflicting advice. Most agree that erythromycin is the only way to get rid of it, but I live in the uk and it's illegal to obtain it without a prescription which I won't get for a fish tank. So that option is completely taken away from me.

What else can I do? I've read to reduce phosphates and nitrates, but I've also read to increase nitrates and increase water flow. I tried a blackout when I got it last time but that did nothing at all!

I've got a 48L tank, two 11w lights over it but about 3/4 of the surface of the tank is covered in floating plants so the amount of light reaching the tank is probably less. Lights are on 4 hours, off 4, on 4, off again. I dose 1ml liquid carbon and 1 drop jbl liquid daily fertiliser every day. My nitrates are 0 at the moment, because of all my plants. I don't know if the plant food should be showing up as nitrates? I am in the middle of going over to RO water from tap water. So it's probably about half and half at the moment.

Sorry for the essay but I wanted to give as much info as possible before people had to ask for it

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[Jkeating8]

Cyano thrives in environments low in nitrate. Increasing nitrates will help rid the problem assuming yours are actually at 0.

 

[Fishies86]

How do I add nitrates then? I'm assuming the plant food I'm adding isn't increasing the nitrates then. Or do I need to increase the ferts? How do you know if you need to increase them? I don't want to overdose :/

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[Delapool]

You can spot treat with hydrogen peroxide - just do a search for it.

 

[Brookster123]

How do I add nitrates then? I'm assuming the plant food I'm adding isn't increasing the nitrates then. Or do I need to increase the ferts? How do you know if you need to increase them? I don't want to overdose :/ Sent from my GT-I9505 using Aquarium Advice mobile app

add more fish?? More fish poo.. More nitrates??? Is it that simple?

 

[preyas1207]

do you still have other plants in there? consider turning off the heater for now since blue algae grows best in warm water it will just pause the growth of it. Blue green algae is making the water blue am i correct? i would maybe try some cherry shrimp and otocinclus depending on how long your tank has established try to have it atleast 3 months, otocinclus stay small and wont uproot any plants

 

[Fresh2o]

I had a bout of cyano for several months. Did not know what it was. During water changes it was easy to remove. Finally picked up some erythromycin (EM) at Petsmart and dosed it for 4-5 days. Even after day 6-8 it was still dying off. EM had no ill effects on the plants or fish or snails or filter.

 

[Fishies86]

I can't get hold of erythromycin though coz I live in the uk I don't have that option which is a pain because it seems to be the one thing everyone agrees actually works!
Preyas, I have loads of plants in the tank at the moment. I can't turn the heater off in my tank because of the fish I have in there. I've already got otos in there and cherry shrimp but they don't eat Blue green algae.

Brookster, I'd love to add more fish but I'm already pretty heavily stocked. It's a 48L tank with 7 emperor tetras, a female fighter, 2 otos and some shrimp. I don't think it'd be fair on the fish to ram any more into my little tank. Or do you think it'd be ok to add more as I wouldn't have a problem with high nitrates?

I checked all the plant food in my lfs and it's all phosphate and nitrate free! Surely there must be some with nitrates in?

Hydrogen peroxide? Is that not harmful to the fish? I'll look into treating with that, but I still need to eliminate the cause otherwise it's just gonna come back again isn't it.

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[Delapool]

Peroxide won't be harmful at correct dose. Your right though, better to find the cause.

 

[Rivercats]

Cyanobacteria doesn't turn water blue nor will any type of fish, shrimp, or snails generally eat it. You should be able to check around and look into getting a fertilizer with a high nitrate amount of see if you can find KNO3, Potassium nitrate, online and order some. It's a dry fert. Or Seachem make Flourish Potassium which is very easy to use. You want at least 10ppm of nitrates in tank water. Anything lower than that can make a tank more susceptible to Cyano growth.

What you can do is manually vacuum out as much as possible then use 3ml hydrogen peroxide 3% solution for every 1 gallon of water. Turn off you filters, squirt the Cyano with the peroxide, leave filters off 20 minutes. Then do a 3 day black out. Completely black out the tank and no peeking or you'll break the black out cycle. Once done do a large 60% WC and only run lighting 6 hours daily. Be sure not to overfeed as many fish foods can add excess phosphates to the tank. Lastly do at least a 50% WC weekly.

If you recently set you tank back up again you might have gotten an ammonia spike which can also attribute to Cyano.

 

[Fishies86]

Sorry it's taken me so long to reply, ive been so busy recently that I haven't been on here for ages!
I managed to get some potassium Nitrate. I split the dosage down and now dose 5ml every day. This is maintaining the nitrates in the tank at about 5-10ppm. I also got some malaysian trumpet snails to stir up the sand substrate. Ive also kept up with doing ny water changes with RO water so think it's mostly RO now. One of these things or, more likely in my opinion, all of them has really reduced down the cyanobacteria. There are still a couple of small patches on the glass just above the sand substrate but there is a marked reduction! Im so chuffed!
Thanks for all your help guys! Love how helpful everyone is on this forum!

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