# HELP! Cyano is destroying my tank.



## gBOYsc2 (Dec 4, 2010)

Please help. I have been battling cyano for a few weeks now and nothing is working. 

At first, it only started to appear in a small area where the spraybar didn't reach. So I thought it might have been flow related so I bought a second spraybar and extended it the whole length of the tank. Then it started to spread to other areas. So I checked my nitrates and they were 40-80ppm (I couldn't tell the colors look very similar on the test kit). So I decided to only dose half the amount that I was dosing. This only seemed to make it worse. So then I tried removing the spraybar, added a small HOB on the exact opposite corner of the tank that the water returned while going back to regular KNO3 dosing and again, the cyano just progressed.

I also tried tweaking the CO2 while doing this.

I'm at a loss. It has spread to nearly every plant in the tank and is slowly killing them. I don't know what to do and I have tried nearly everything. Can anyone help me please. It has gotten so bad that it is just depressing to look at my tank and I am considering shutting it down.

I decided not to go for the blackout method because that would only be a temporary fix and wouldn't actually solve the problem. I have dealt with this stuff in the past and I know how fast it can come back. In the past it was as simple as adding nitrates to fix the prob but I am not sure this time as I have tried both low and high nitrates.


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## Jadelin (Sep 30, 2009)

Since you said you've tried everything, I assume you've seen advice like this before, but this is where I always go if I have algae troubles: http://www.jsctech.co.uk/theplantedtank/algae.htm

What is your lighting like? Does your tank get direct sunlight? Light shining directly on the substrate from outside the tank can cause BGA.

BGA apparently LIKES low nitrates (<20 ppm), so it's a bit strange that it's doing so well with your nitrate so high. Algae aside, if my nitrates were 40-80 I'd stop dosing them altogether until it was back in the 20-40 range, and then figure out what I needed to dose to keep them there.

What is your maintenance schedule like? How often and how much do you do water changes? How often do you clean your filters? How heavily planted is your tank, and if there are areas of substrate not covered by plants, do you vacuum them when you do water changes? I've heard built-up mulm that's not being used by plants and dirty filter media can also contribute to BGA.


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## gBOYsc2 (Dec 4, 2010)

Thanks for the reply. Yes I have seen several websites similar to that all noting that low nitrates or insufficient flow will cause this.

I have 48w of T5HO lighting on a standard 20g tank. The tank does not get any direct sunlight but is in a room that is sunlit during the days.

I dose EI and do 50% water changes per week. I also try to clean the filter every month but sometimes let it slide to 6-8 weeks. I also forgot to mention that I cleaned the filter in my attempts to rid of the BGA.

The tank is completely filled with plants and there is absolutely no open substrate. Im wondering if it is mulm collecting in the large bushes of plants that could be contributing. 

I'm considering manually removing as much BGA as I can, removing all of the plants, trimming- replanting, and doing a good gravel vac.


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## Jadelin (Sep 30, 2009)

Wow, that's a lot of light! Usually you get different kinds of algae with high lighting like that, but it might be contributing to the BGA; I would definitely try cutting down that light. Does the fixture allow you to run just one bulb? One bulb T5HO on a tank that size should give you plenty of light to grow whatever you want.


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## Wasserpest (Jun 12, 2003)

Really simple to kill BGA. Search for *Erythromycin* on this forum, a lot of good discussions should pop up.


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## Crispino L Ramos (Mar 29, 2008)

Get rid of it with Maracyn (follow directions in the box).

http://www.fosterandsmithaquatics.com/product/prod_display.cfm?pcatid=4838&rel=1


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## gBOYsc2 (Dec 4, 2010)

Ive had the tank running with that light for a few months. Nothing has changed in my maintenance or anything before the BGA started to appear.

Does erythromyacin or maracyn kill my bio filter?


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## Crispino L Ramos (Mar 29, 2008)

It will destroy some bacteria like cyanobacteria but not all bacteria because it's not a broad spectrum antibiotic. You can do a large water change after the cyanobacteria is gone and introduce mulm (save the filter mulm to re-introduce into your tank after the treatment and water change).


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## kevmo911 (Sep 24, 2010)

If you use an antibiotic, consider either not running the filter or removing the filter media and replacing it after water changes.


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## Wasserpest (Jun 12, 2003)

IME it doesn't kill the biofilter directly, but if there are large masses of cyanobacteria dying this might still lead to a spike (which plants usually gobble up in no time).

You might want to vacuum/clean out some of the larger BGA accumulations before adding the pills. Also, make sure you have enough on hand for the full 5 day treatment.


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## houseofcards (Mar 21, 2009)

gBOYsc2 said:


> Ive had the tank running with that light for a few months. Nothing has changed in my maintenance or anything before the BGA started to appear.
> 
> Does erythromyacin or maracyn kill my bio filter?


Just because it was running for a few months doesn't necessarily mean it's sustainable long-term. Organics build-up over time. What are your organic load factors (fish, feeding). What is your light cycle? Are you plants growing well?


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## gBOYsc2 (Dec 4, 2010)

Thank you dearly everyone for all of the reply's. I went out and bought some API E.M. Erythromycin today. I am going to give it a shot. The tank is very lightly stocked and HEAVILY planted so I am not so worried about the bio filtration being destroyed. I'm hoping the plants will use up all of the ammonia, nitrites and nitrates.

@houseofcards. The organic load is very small. I have ~15 threadfin rainbows and a couple amano shrimp in there. I feed them very sparingly only as much as they can eat in 30 sec to 1 min every day or 2nd day. I leave the lights on for 8 hours a day and the plants grow very very well.

@wasserpest - The filter is well established it was running on a 50g tank previous to this for a year. I will try to manually remove as much of the cyano as I can before adding the erythro.

Again, thanks so muchh. The erythro is my last ditch effort before a blackout.

While dosing the erythro should I dose ferts and keep everything normal? Leave the lights on, turn them off?


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## houseofcards (Mar 21, 2009)

gBOYsc2 said:


> ... Im wondering if it is mulm collecting in the large bushes of plants that could be contributing...


This is the Reason I asked about your organic load. If you have strong light and have alot of mulm sitting around and collecting that to me is a recipe for problems.


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## fishykid1 (Apr 5, 2010)

Jadelin said:


> Wow, that's a lot of light! Usually you get different kinds of algae with high lighting like that, but it might be contributing to the BGA; I would definitely try cutting down that light. Does the fixture allow you to run just one bulb? One bulb T5HO on a tank that size should give you plenty of light to grow whatever you want.



I had that light on a 20G as well... Never had a problem other than minor GDA, once everything settled in and matured. BGA is nasty stuff though. I had it once, and I literally increased surface movement a little and increased flow through the tank, it went away immediately. (5 days)


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## MarkMc (Apr 27, 2007)

IMO high organic loads, high light and poor CO2 will make it tough to rid the tank of it. Decaying plants are also a source of organics too so just because you don't overfeed doesn't mean you may not have a problem with that.


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## fishykid1 (Apr 5, 2010)

MarkMc said:


> IMO high organic loads, high light and poor CO2 will make it tough to rid the tank of it. Decaying plants are also a source of organics too so just because you don't overfeed doesn't mean you may not have a problem with that.



That was the other thing I forgot to mention.. organics...


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## chad320 (Mar 7, 2010)

Be careful, im thinking erithromycin will kill your yamato shrimps.


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## gBOYsc2 (Dec 4, 2010)

I will have to temporarily re home them I guess until the tank is clear of erythromycin. Luckily I have a 1g cube with just mosses and a couple baby guppies which will be a perfect temporary home for them.


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## gBOYsc2 (Dec 4, 2010)

Does anyone know how much, how often and how long to dose the erythromycin for? I'm have no clue how to dose this for cyanobacteria. It only has instructions for fish diseases on the box.


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## Wasserpest (Jun 12, 2003)

Here is my recipe:

200mg per 10 gallons for the first dosing
Do a 10% waterchange after 24 hours, then add 100mg per 10 gallons
Repeat that (water change and dosing) 3 more times for a total of 5 doses during 5 days.

The EM tablets I have seen are usually 200mg. Adjust if they are different.

So for your 20 gal tank, add two tablets for the first dosing, and one tablet for each of the successive doses (total of 6 200mg tablets).

Cyano should start to die during the 3rd day or so, but keep dosing for all 5 days.

I hope I don't get cyano in my 250gal tank. Expensive treatment right there.


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