# Blue green algae/cyanobacteria



## mattinmd (Aug 16, 2014)

There's a lot of conflicting information about algae in general out there.. Algae isn't all that well understood. Other than green water, there's no well understood ways to intentionally cultivate specific strains of algae. If we don't know how to grow it, well, understanding of how to control it is limited.

That said, less than 5ppm of nitrate is definitely not good for the health of your plants. Plants need nitrate to grow (along with phosphate, potassium, etc, etc). Weak/suffering plants suffering from deficiency seem to invite photosynthetic organisms that are less demanding, like algae and cyanobacteria.

As for getting rid of BGA, the two usual "kill it off" techniques I've seen used here are blackout and erythromycin...

Blackout just involves turning the lights off and covering the tank (no room light either) for 3 days. No light, no food. Yes healthy plants and fish will survive the 3-day fast. Life in the wild often involves going hungry for a few days... (in the case of plants, 3 days of deep cloudy storms is uncommon, but a totally natural occurrence and doesn't seem to harm anything)

erythromycin is an antibiotic that seems to kill off BGA pretty quickly. I'm not sure offhand if cories are sensitive to it or not.

Of course, neither of these methods offer any kind of long term control.. if good conditions for BGA continue, it will come back.


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## hachi (Jul 30, 2015)

Thanks for the reply! I assume as I add more fish I'll be able to maintain a higher level of nitrates. For now do you think I should start adding some nitrates, maybe get a little bottle of the seachem stuff? Thanks for the help.


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## mattinmd (Aug 16, 2014)

The seachem Nitrogen would be one way to raise your nitrates.. Their comprehensive product is mostly a micronutrient fertilizer, and only contains a trivial amount of nitrate.

I will caution you that the Seachem fertilizers are very expensive in the long run (those bottles are mostly water...), but for short-term use on a small tank they should be fine. 

As you get into fertilization long term, I suggest getting a .1 gram scale and dry fertilizers to mix your own. A pound of KNO3 is going to be equal to many gallons of the seachem stuff.


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## hachi (Jul 30, 2015)

Yeah, I'm sure they would be super expensive in the long run. But they are locally available so I can get them today. I'd probably have to find a source for the dry stuff online. Thanks again!


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## mattinmd (Aug 16, 2014)

nilocg sells them over in the for-sale forum here, I've used him before.

Or you can get them online, one place a few folks here keep mentioning is:

http://greenleafaquariums.com/


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## hachi (Jul 30, 2015)

Thanks! Appreciate all the help.


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## Doppelgaenger (Jul 20, 2015)

I had a bit BGA outbreak due to me adding too many ferts and not changing the water because I had newborn Orange Sakuras and Ghost shimp.

I ended up having to pull EVERYTHING out of the tank and boil it to kill the damn stuff. It will grow slowly until it suddenly explodes if you don't address the root cause.

Change the water often and vacuum your substrate to get rid of all the organic matter. This did it for me. Keep it clean and it probably won't come back

Also, turning off your filter and spot burning the stuff with H2O2 from an eyedropper is very effective, but you have to be consistent and hit each spot at least three times within 8 hours to kill it completely. If anything is still alive after you've burned it, it'll grow right back.

As long as you don't have flow in the aquarium, don't worry too much about how much you dose, H2O2 is heavier than regular water and will sink into the substrate where it won't mix in with your water column, just keep the flow off until it's had some time to be broken down by the light.


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## koiboi (Sep 4, 2011)

I have 15 column tall tank which is a challenge for growing plants. When I had BGA it was growing (quickly) along the bottom. Like you, I found conflicting information on how to get rid of it. What worked was a series of water changes, sucking out as much as I could (at which point my bf came downstairs and said "Why does it smell like grave dirt down here?" which it kinda does) and placing a small circulating pump at the bottom of the tank. It seems like the BGA doesn't like flow. I did use Erythro to eradicate it as a precaution and it didn't harm my dwarf cories. The only time it came back was when the flow stopped due to a clogged pump. A water change and re-establishing the flow fixed it without more antibiotics.


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## Doppelgaenger (Jul 20, 2015)

You aren't kidding about the Grave Dirt thing... that's a perfect description of the smell

You know when a tank is getting better, cuz you can't smell the stink anymore.


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## klibs (May 1, 2014)

I agree with all of Matt's posts

IMO BGA is the easiest 'algae' to get rid of (it is actually just bacteria and not algae at all).

If you manually remove BGA and it comes back then you need to fix the root cause. Just removing some of it does not fix anything and IME every time I have had BGA it was easy to fix by making sure I was on top of the following:

- Get good flow throughout your tank. Dead spots where organic matter builds up are great for BGA
- You may just have too much light
- Nitrates (everyone says this but this has never been an issue for me)
- CLEAN UP YOUR TANK WITH WATER CHANGES. BGA is the first thing to come whenever I slack off on cleaning my tank and vacuuming out organics.

You can get a head start by removing it manually and blasting whatever is left with erythromycin (or whatever it's called) or even H2O2. I have used H2O2 with success.

Again, if I do the above BGA never ever ever comes back unless it has a good reason to. Whenever it comes back it is 100% my fault and preventable


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## Doppelgaenger (Jul 20, 2015)

I'm starting to think that it's pretty much Organics that are the main cause of BGA. And the last time it got really bad was due to me overfertilizing because I was a dumbass that couldn't read a bottle, coupled with overfeeding because I was trying to keep baby ghost shrimp alive (I actually got two to settle down out of the larval stage).

Ever since I started using a substrate vacuum my aquarium has been doing so much better.


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## klibs (May 1, 2014)

Yes - organics break down and all algae loves it. If you do frequent water changes and keep things CLEAN then algae is much worse off and your tank will thrive.

Overfeeding is a great cause for BGA and other algae. I feed my fish a lot less now after noticing some BGA and random outbreaks and it has made a world of difference in my high tech tank. Less fish poop + less broken down food = far less organics = fewer algae outbreaks.


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## mattinmd (Aug 16, 2014)

+1.. part of me also wonders if the nitrates really traces back to organic waste issues...

Low nitrates causes dead/dying leaves which fall off and become BGA food.

Sufficient fertilizers (in general) causes healthy plants, less leaf litter, less BGA food.


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## Doppelgaenger (Jul 20, 2015)

I didn't have any significant plant die off myself because I didn't have that much in the way of plants that would melt (Java fern). I never did test at that point to know what my nitrates were, but keeping shrimp and fish poo in the tank as low as I can has kept me BGA free since.

That and not massively over-dosing Flourish.


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## Donald Corbett (Apr 1, 2015)

mattinmd said:


> +1.. part of me also wonders if the nitrates really traces back to organic waste issues...
> 
> Low nitrates causes dead/dying leaves which fall off and become BGA food.
> 
> Sufficient fertilizers (in general) causes healthy plants, less leaf litter, less BGA food.



I think there's a lot of truth to what you just mentioned. The only times I've ever had BGA personally was when I added a good bit of immersed plants. Naturally they lose some leaves and go through a rough patch at first before they adjust and take off. Once everything is growing healthy it disappeared. This has happened in two separate tanks. 


Sent from my iPhone using Tapatalk


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## koiboi (Sep 4, 2011)

I can't +1 klibs enough on the flow. I said it in my post, but worth saying again. I think maybe dead spots just have the low O2, high concentration of organics BGA loves. Problem is once it gets going it migrates out of the dead spots all over the place. Klibs is also right in that BGA out breaks are our own faults; any time I get it I kick myself for slacking on something I know will bring it back!


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