# Blue-green algae on one kind of plant only



## Igor Kosarev (Sep 4, 2006)

Dear colleagues-hobbyists,

My name is Igor, I am from Russia, Saint-Petersburg. 
I have been trying to keep plant tank. It is 300 liters tank (79 gallons?). Water condition is the following: 
t=25-27 C, 
gH=2-3, 
kH=3-4, 
pH=6,5, 
NO3=5-10, 
NO2, NH4, PO4=0
Fertilization - Dennerle kit (1/2 from recommended dose
Filtration - JBL-250 with Sera Siporax
Lighting - 4x30W - 10 hours (one Hagen Flora-Glo, two Sylvania Gro-Lux and one LB (Russian cheap quasi analog of Hagen Sun-Glo).
I change 50 liters every Sunday and 1 tea spoon of K2CO3 and 20 ml CaCl (10% solution) and 20 ml of MgSO4 (13% solution) to increase kH and gH of tap water (thee are kH=0 and gH=0).
Fish - 6 Scalarias, 1 SAE.
In my aquarium there are a lot of plants and all plants show good growth and perfect appearance. 
However from time to time one kind of algae appears. It is blue-green algae. It is amazing but they appear on point of increase of only one plant - Myriophyllum Mattogrossense (?). You can use the link on the below to see my problem.

http://www.private.peterlink.ru/kosarev/mypage5/pictures/2136l.jpg

I can improve situation if I add Erythromycini. But algae may appear again in one or two months.
I would highly appreciate if you share your successful experience in fight against blue-green algae.

Best Regards,
Igor


----------



## jeff5614 (Feb 15, 2006)

That's interesting. If you merely wipe it off the plant how long does it take to reappear? I had a massive BGA experience in a non-planted a few years ago and used erythromicin to get rid of it. After that I converted that tank to planted and haven't seen any since.

I guess that doesn't help much so I hope someone else will chime in.


----------



## $eaba$$ (Dec 6, 2006)

*Bga*

Not to hijack thread, as the author of this thread may want to know also, where can u get erythromicin?


----------



## jeff5614 (Feb 15, 2006)

$eaba$$ said:


> Not to hijack thread, as the author of this thread may want to know also, where can u get erythromicin?


You can get it at your lfs. It's sold under than brand name of Maracyn and I'm sure there are other brands also. Just read the list of active ingredients on the package to be sure. Don't buy Maracyn-Two as it's a different antibiotic.


----------



## aloha (Jun 2, 2005)

If the bga algae appears in certain leaves in small patches only, you don't need to mess with e-mycin. Cut the affected leaves, improve the water flow and dose nitrates with KNO3.


----------



## Igor Kosarev (Sep 4, 2006)

Dear aloha,

What does it mean - "improve the water flow"
Do you think that 5-10 mg per liter of nitrate is too low?

Best Regards,
Igor.


----------



## aloha (Jun 2, 2005)

Bga algae usually appears in low flow and stagnant places. Observe if enough water flow blows around the plant. I see you have only one filter. Maybe you should place an extra powerhead to improve the tank's total flow? 

I see you don't dose any nitrates so we don't really know if the 5-10mg NO3 is a correct measurement (which could be 1ppm or 15ppm) unless you have previously calibrated the NO3 test. If you search around the forum most folks are uncertain about the accuracy of the usual water tests.


----------



## Igor Kosarev (Sep 4, 2006)

Dear All,

Since last message I have tried lot of cure method - like cutting of tops, additional water flow and nitrat level increasing. But did not help. When it started to appear on gravel and other places I put Erythromycini 500 mg to 300 liters (last Sunday)and now I have healthy tank without any BGA.

Best Regrds,
Igor

http://www.private.peterlink.ru/kosarev/mypage5/pictures/4984l.jpg


----------



## trong (Aug 8, 2006)

my 2 cents. you can have bga even with good N levels if you don't have Po4 because you need N, P, and K and trace to keep nitrate from locking up. which if i remember correctly is why bga appeares. I hope this is correct and it helps as i am going from memory, and if its not someone will correcty me.


----------



## MatPat (Mar 22, 2004)

Good catch Trong. He is not adding any PO4 to the tank so the NO3 uptake by the plants is probably very low. I would guess that is the cause of the BGA since he has tried the other recommendations. 

Try manually removing the BGA and adding a some PO4 to your tank. Here in the US a lot of people are keeping fairly high levels of PO4 in their tanks. I try to keep my PO4 levels around 2ppm (2ml per liter). This works pretty well for me. You may find that when you start adding PO4 to your tank you may need to increase your NO3 additions as well. I had some low NO3 issues (BGA and decreased plant growth) when I first started to add higher amounts of PO4.


----------



## hoppycalif (Apr 7, 2005)

With only about 1.5 watts per gallon of light you don't need a lot of fertilizing, and it is possible to just follow Diana Walstad's el natural method with that much light. The way that type of tank gets enough nitrate and phosphate is through heavy feeding of the fish, as I remember. If it were my tank I think I would try dosing about 2 mg per liter of phosphate, about once a week. If it works the effect will be easy to see almost immediately. It might cause the nitrates in the water to all be used up quickly, so that would make the problem even worse. Thinking as I type, which is rarely great idea, maybe the best idea is to do weekly dosing of both nitrates and phosphates.


----------

