# BGA problem



## BobinCA1946 (Jul 28, 2009)

Okay so I am getting a coating of BGA on my substrate and plants.
I read that it is caused by a NO3 deficiency.
My tank is running at approx. 80 ppm of NO3.
I tested this using a "calibrated" test kit.
What is the desired level of NO3?
Anyone care to give me a solution?

Regards,
Bob


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## Seattle_Aquarist (Mar 7, 2008)

Hi Bob,

You have excellent timeing, I am just finishing up an article concerning my experiences with Cyanobacteria (BGA) for our local club newsletter. Do me a favor and give it a read and tell me if it is fairly easy to follow.

Thanks,
Roy

"Last month I mentioned that I had a “dirty little secret”. I explained that I did not bring plants to the March meeting because I have been fighting cyanobacteria, also known as Blue-Green Algae (BGA), in one of my tanks and I didn’t want to share it with others. After six weeks of trying different methods I seem to be making major headway and will share what is succeeding for me. 

As I write this it has been exactly one week since I finished treating an outbreak of BGA in my 30 gallon aquarium. I believe it started because I let my nitrates (NO3) get too low and missed a couple of water changes. In addition I hadn’t cleaned my canister filter for several of months so debris had built up and the flow and circulation had dropped in the tank. Any or all of these conditions could have been the cause for my outbreak.

Here how I got rid of it. First I worked on the causes. I cleaned my canister filter and added an airstone (I would have used a Koralia Pump or powerhead if I had one) to increase circulation. I increased my fertilizer dosage to 1/8 teaspoon (tsp) of KNO3 (potassium nitrate) and 1/64 tsp of KH2PO4 (monopotassium phosphate) per 10 gallons daily. Lastly I increased my 33% water changes to twice a week.

Next I went to work on the algae. I siphoned and manually removed as much of the BGA off of the substrate, plants, and hardscape as possible and cleaned the glass. Most of the easy-to-replace plants I threw out. I removed most of the hardscape from the tank, scrubbed it, rinsed it, and put back in place. It was very important to remove as much BGA as possible before doing the next step to minimize oxygen depletion, and fish death, from dying algae.

I treated the BGA with Hydrogen Peroxide 3.0% (stabilized) solution. Hydrogen Peroxide (H2O2) is available at most grocery stores, pharmacies, and drug stores. I also picked up a 10 ml dosing syringe (for oral dosing of medications) at the drug store when I picked up the H2O2. 

I always did this part of the treatment when I knew I was going to be around for at least a couple of hours afterwards so I could watch my fish for signs of distress. I only treated the tank after the lights (about 2 WPG compact florescent) had been on for at least two hours so photosynthesis was occurring at its’ maximum in the BGA. I found that the BGA reaction to the treatment was strongest, and fastest, in the areas of the aquarium with the brightest light (and the most photosynthesis).

I turned off my filter about 5 minutes prior to treatment to minimize water movement. I dosed the 3.0% (stabilized) H2O2 at the rate of 1.5 ml per gallon of water volume (my 30 gallon tank has 24 gallons of water in it). I put the H2O2 in a glass, filled the 10 ml syringe, stuck my hand in the tank, and s-l-o-w-l-y “painted” the areas where the BGA was heaviest with the thickest “clumps”. I added the H2O2 at a rate of about 10 ml per minute so as not to stress the fish too greatly.

The effect was rapid and dramatic. After several of minutes the areas of BGA I had “painted” with the H2O2 began to bubble (gas) and started to turn a rusty brown. After about 30 minutes the “painted” areas were bubbling intensely and had turned a definite brown color while other areas of the tank (where I had not “painted”) were also bubbling (but not as intensely) and starting to turn rusty brown. After about an hour the water in the tank had a slight “rusty” color, the areas or BGA I had “painted” were a definite brown, areas of BGA that were heavy but had not been “painted” had some of the brown, and plant leaves that had a film of BGA and a film of brown. After one hour I turned the filter and airstone back on and continued to observe the fish for any signs of distress for an additional hour. After a couple of hours the water cleared and the fish become more active. After 24 hours the areas I had "shot" had turned a grey color and the BGA appeared dead.

I followed the same procedure for dosing the next day again dosing the areas with heaviest algae that was yet dead. The dosed areas bubbled and turned rusty but there was not as much bubbling and rust in other areas (I think because areas with a light coating of BGA had been killed on the first day), the water did not changed color as much, and bubbling activity and any discoloration cleared in about 2 hours.

Each day for a two week period I followed the procedure I described above. Each day the amount of BGA diminished and after about 8 days the BGA appeared to be gone. I continued the treatment for an additional four (4) days just to be sure there was no residual “hiding” in the crevasses of my driftwood or under plant leaves. It was not necessary to hit the BGA directly with the hydrogen peroxide to kill it. For example, on the edges and undersides of plant leaves I did not “paint” the areas but after about 5 days the BGA had turned rusty brown, was breaking away from the leaves, and was falling off.

As a side note I also had an outbreak of Black Brush Algae (BBA) in this same tank; probably due to the low CO2. The treatment described above worked on it as well, but the BBA did have to be “painted” to die and areas in bright light responded the best to treatment."


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## BobinCA1946 (Jul 28, 2009)

Roy,

It reads quite easily. 
Unfortunately it only concerns itself with the treatment, not the cause.
My questions were not answered ie: why do I have BGA, if my NO3 is way too high (approx. 80 ppm)?
What is the NO3 parameter (ppm) that is recommended?
I am running pressurized CO2 and 6 x 55w PC's.
Bob


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## joshvito (Apr 6, 2009)

Bob,
What size is your tank?
And how much water movement do you have?

When you test for nitrates, where do you pull the water from?
The middle of the tank? Surface? Near the BGA?

What is your dosing WC schedule?
Stocklist?

These are all things that can help us(APC community) diagnose your problem.


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## Seattle_Aquarist (Mar 7, 2008)

Hi BobinCA1946,

There are several reasons given for an outbreak of BGA that I have read including dirty filters filled with decaying debris resulting in reduced circulation; low nitrate levels (my tanks typically are 30+ ppm) and / or ammonia present, infrequent or inadequate water changes, or my favorite "just because".

I don't believe that high nitrate levels by itself will resolve the problem. In water treatment plants some species of BGA thrive in high nitrate environments.

I tried a treatment with Maracyn (antibiotic) prior to the treatment outlined above and the BGA slowed growing but did not die and continued to spread after the treatment was completed. 

I do believe that 2X (or more) week water changes do help any treatment attempted. Algae, being a “lower” evolved plant form, does not adapt well to changing water conditions like the "higher" more evolved plant forms (like stem plants) do. So regular water changes seem to be indicated both to augment a treatment and to reduce the likelihood of an outbreak.


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## BobinCA1946 (Jul 28, 2009)

joshvito said:


> Bob,
> What size is your tank?
> And how much water movement do you have?
> 
> ...


My tank is 125 gal. plus a 25 gal. sump beneath.
I have two Koralia's operating at either end of the tank to aid in circulation.
I tested the water from near the surface of the aquarium.
I change out 50% of the water every weekend, or at least every other weekend.
My tank is stocked with 8 Congo tetra's; 9 Boesmani Rainbow's; 6 Rummynose; and 1 Discus.
All fish are fully grown.
I have been dosing 1 tsp. of KNO3 every day along with traces and PO4.

Bob


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## joshvito (Apr 6, 2009)

Do you add carbon? Dosing that much KNO3 without added CO2 or excel may be your problem. What is your substrate? Capped soil? Gravel?

Do you have any photos of the BGA?

How much structure or plants are in there. A photo will help us understand your issue.

Most times BGA is a low flow, nitrate deficiency problem. I have heard of marine aquarists with high nitrates also battling the bacteria. 

I suggest doubling your WC schedule, and cut your dosing in half. During each WC, remove as much BGA and mulm as possible. Also check your sump for mulm buildup.


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## BobinCA1946 (Jul 28, 2009)

Joshvito,

Please explain the "chemistry" as to why pressurized CO2 would not be enough to combat BGA where NO3 is high and no other Carbon source is utilized? I do not use Excel at the moment.
My substrate is pond filter sand....totally neutral.
Filter floss in Sump is clean.
I have been vacuuming mulm out of the tank to reduce organics.

Bob


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## joshvito (Apr 6, 2009)

> Please explain the "chemistry" as to why pressurized CO2 would not


I wasn't sure if you were dosing CO2. Try and keep your target of NO3 at 20ppm. And keep a regular WC/dosing schedule.

I still think a photo will help.

Any other APC can you help diagnose?


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## xavierj123 (Aug 24, 2008)

I cured my BGA problem the easy way by using Maracyn from your local pet store. Just follow the directions on the box and be sure to clean your filtration system first and remove the charcoal as the charcoal will not let the maracyn do its job.


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## flashbang009 (Aug 6, 2009)

Maracyn is known to damage the biological filter, as it is an antibiotic. Roy's article is spot on with my experience with BGA. H2O2 will usually knock out BGA within a few days. I had some in a corner of my tank for a few days, i hit it with some H2O2 and it was gone within 24 hours.

As for cause, the MOST important factor that i have seen is water circulation. Without it, the bacteria can gather and grow. The other very important factor(s) is water changes and keeping the filter clean. Make sure your tank meets those qualifications and you should be fine. If you do develop BGA, just use some cheap H2O2!


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## DJKronik57 (Apr 17, 2006)

> Maracyn is known to damage the biological filter, as it is an antibiotic.


And H202 is similar to bleach. Both will damage your biological filter. Just saying, H202 is probably _more_ dangerous for your plants/fish/bacteria if not used correctly.

That aside, I've been battling a bad BGA outbreak as well. I've figured out it was caused by a dirty filter that hadn't been cleaned in a few months and low phosphate levels. BGA apparently isn't only caused by a lack of nitrates, but an imbalance between nitrates and phosphates. If your nitrates are fine (as mine were) it might be worth checking your phosphate levels. Also, I have plenty of circulation in my tank with a 2217 and a power-head, so it was not caused (or cured) by circulation.

I've hit it twice with Maracyn and it does kill it back with no ill effects on the rest of the tank, but shortly after treatment stops, it seems to reappear. Each week long treatment is $20 worth of Maracyn too, so it's not cheap. I also tried a 5 day blackout, and it seemed to slow the BGA down a bit, but it bounced right back once the lights came back on and the blackout did weaken the plants a bit.

*Is there any way of getting rid of established BGA without using Maracyn/H202, or once it's there, it'll survive till you get rid of it?* I'm thinking at this point the only possible way of getting rid of it all is a strong Maracyn treatment combined with H202 spot treatment, but I'd rather not blast my tank like that if possible.


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## Seattle_Aquarist (Mar 7, 2008)

Hi DJKronik57,

I had the same problem/frustration with Maracyn; the BGA returned and it can get expensive. Water changes, and H2O2 after the lights have been one an hour of more so photosynthesis is going strong worked for me. The aquarium is still BGA free after after over a month.


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