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Well, I'm puzzled. I have always thought that the green (blue-green) slime algae was a symptom of poor water quality.

Mine was, until two days ago, as follows:

Temp: 76/24
pH: 6.8
Nitrites: 0
Nitrates: 10
Ammonia/-ium: 0
GH: 40 ppm

Then the nitrates dropped to almost 0 and I found a tiny slime coating forming on my Ambulia (Limnophila indica). Since the slime is, as I understand it, a nitrogen fixer, I think that explains the sudden nitrate drop.

I have low lighting, so the Ambulia grows relatively slowly, but I have a Flourite substrate, so all my plants are growing well and looking good.

I can easily wipe this slime off, but this suggests something that I'm missing. Help, please?

I vote! Do you?

If anything, a nitrogen fixer would INCREASE nitrates. Nitrogen fixing involves converting atmospheric nitrogen (N2) to some sort of oxidized form (ammonia, nitrate, etc.). I can't even imagine the amount of BGA required to increase nitrates, though. I don't even know if they make excess.

Regardless, what this means is that the cyanobacteria can survive in ultra-low nitrate environments where other algae would starve. I know of people who have actually had to dose their tank with KNO3 to allow other types of algae to survive and out-compete the BGA. Babelfish has done it, so she can probably give you more info than I can.

Another level you want to check is your phosphate level. There is a certain ratio of nitrate : phosphate (4:1 off the top of my head, but don't quote me. Again, Babel can probably help more than I can) which is optimal for BGA growth.

If worse comes to worse, you may have to do a total blackout on the tank for a few days. Hopefully, it won't come to that.

Hi,
Here are a couple of sites that will help in understanding
why the outbreak, and how to get rid of the stuff:

cyano.shtml" rel="nofollow" target="_blank">http://www.skepticalaquarist.com/docs/algae/cyano.shtml

http://aquamaniacs.net/forum/cms_view_article.php?aid=137

Hope this helps...
Frank



-->>> The Confidence of Amateurs, is the Envy of Professionals <<<--

I'm an historian, not a chemist, so please bear with me here, as this is out of my area entirely...

A nitrogen fixer would up the nitrate level, rather than drop it? I had thought that the slime would take the nitrate out of the water, not the other way around. Sounds like I've got this entirely backwards, Joe?

The articles are great, thanks, Frank.

I do want other algae to be able to grow, as I have 3 Otos. Should I get a phosphate testing kit? Would it be alright for me to PM Babelfish?

I vote! Do you?

Hi Twilight,

Potassium permanganate (pp) is available at places that sell water softener chemicals for your home. Even of you can get a couple grams you'll have lots left over

In a container just large enough to hold your plants, fill with tankwater, mix tiny amounts of pp in at a time, stirring each time, until the water turns purple (not pink). Completely submerge the plants in there for exactly 10 minutes.. You may have to use something to weigh them down and hold them under. Take extra precaution to NOT get this stuff on your skin. Chemists recommend gloves, I use chopsticks for moving them. Rinse the plants very well with about the same temp water.

Replant them, do a 1 week blackout. Then change your photoperiod to 10hrs if it was more. Increase water circulation in the area that was affected.


The Amazon Nut...

Yeah, you've got it backwards. Nitrogen fixation is converting atmospheric nitrogen to nitrate or a similar compound.

Will your BGA actually increase the nitrate level in the tank? Almost certainly no. There is no benefit for BGA to provide nitrates for other types of algae, although if you want to read about mutualistic relationships among nitrogen fixtures, this is a quick but interesting article. Given the opportunity, cyanobacteria will just use nitrates in the water, but if none are present, the cyanobacteria probably just fixes enough nitrogen for itself.

Thanks, Moss, I'll hold those instructions in case I get desperate. So far, I removed what little there was while vacuuming and I can't see it coming back yet.

Joe, thanks, I've read the wiki articles, and I'll probably reread them a few times until I get it straight.

So, as I understand it, as the tank matures it's likely to be less accommodating to the BGA anyway. I've lowered the water level just a little and that's increased the water circulation.

I vote! Do you?

Is there any harm to have algae in a tank? I keep my glass clean but I actually like it when there is some growth on the wood and rocks.

Hi,
No, as long as it is not the BGA variety, there is no harm
in allowing algae to grow in the tank. The problem is that
once it starts it can rapidly take over the tank out
competing plants for nutrients, and creating a real mess.
For most, it is actually easier to remove it as it starts
to grow, rather than trying to remove it once it has a
foot hold on the tank.
Frank


-->>> The Confidence of Amateurs, is the Envy of Professionals <<<--