Showing posts with label string algae. Show all posts
Showing posts with label string algae. Show all posts

Sunday, June 17, 2012

String Algae, Blanketweed, Filamentous Algae

More talk about string algae:

A solution to it, if it's a problem for you.
To get rid of string algae or blanketweed, add about 1 quart of hydrogen peroxide per 1000 gallons of water.  When the algae grows, clean out as much as you can and just pour the peroxide in.  It gets rid of all of the algae.

Is the string algae a bad thing or just some people don't like it. We have it growing on our lilies and it doesn't bother us.

It's an OK thing. It keeps the pond clean and clear. Fish love to eat it, but can't stay ahead of it. I never mind it, but most folks simply can't bear it. I get more letters about blanketweed/string algae than anything else.

Wow I kinda like it lol. Blanketweed is that the algae on the bottom attached to the liner?

Pondlady again:  
Blanketweed is the stuff that looks like angel hair spaghetti. You can get it out of the pond with a spaghetti fork if you wish.

The conversation continues:  
Thats funny, I think I know what you're talking about it was on the waterfall awhile back, whole thing gets covered in algae and one good rain storm its all gone.

Another answer:  
All ponds should have a nice blanket of algae along the sides of the pond that should be about 1/4" to 1/2". At least, that's what mine are like although one pond has no algae along the sides that I can see. I wonder if this has anything to do with the alkalinity of the water.

Pondlady again:  
Algae on the sides of the pond can only help with pH. If a pond is balanced properly, a healthy pH of about 7 happens automatically.

You can learn all about algae, blanketweed or just plain pond scum in my book, "A Practical Guide to Building and Maintaining your Pond", available here.

And visit us at for more conversations like this one and lots more.
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Saturday, May 19, 2012

Filamentous Algae aka Blanketweed aka String Algae

We get questions:

Hi, It's me again.

I worked furiously in March to clean out my pond, and you all were a great help. However my enthusiasm, and your great help did not prevent the weather in PA from going cold for the month of April. So I let my pond sit, with the waterfall going 8 hours a day from mid March to now.

I have been calling nurseries around here waiting to get some new plants in there, and then once the plants came in I would put in the fish (I found a guy for that too) however, looking at my pond 2 months after the clean out i see what looked like a green haze, or some fine green cotton candy, I pulled some out and see that it is more like seaweed.

Is this good (that I have food for my future fish), or is this bad (that all the stuff I tried to remove in March is coming back), or something in between?

FYI the nurseries around here are claiming that the water plants should not go in until memorial day.

Thanks in advance


That is filamentous algae. Which species it is is difficult to determine without a microscope. Note that it is most abundant just below the waterfall, where there is a strong current. It likes moving water. Your pond area looks susceptible to influx of nutrient from rain runoff. Nutrient runoff into the pond, especially phosphorus, is the likely source of your algae growth. With your small pond, the best treatment is to first stop the runoff into the pond and then manually remove the algae. I suggest the use of a toilet brush.

Here is a good article on filamentous algae in ponds:

Filamentous algae

More discussion:

After you remove as much of the string algae as you can, you can use Microbe-Lift PL to keep it gone.  H202 works too. Also I have poured a can of beer in a week and that works. Cheap beer.

But the fish do love to eat it.  It's we humans who think it's awful.

Put plants in your pond after the last danger of frost has passed.

You can read more about blanketweed, aka filamentous algae, aka string algae in my new book, A Practical Guide to Building and Maintaining a Pond" Download it here

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Friday, June 11, 2010

String algae/blanketweed

To get rid of string algae or blanketweed, add about 1 quart of hydrogen peroxide per 1000 gallons of water.  When the algae grows, clean out as much as you can and just pour the peroxide in.  It gets rid of all of the algae.

Thursday, May 27, 2010



What is the best treatment green pond weed? It's like green cottonwood.

Blanket weed is what you have. It's difficult to get rid of and Koi will not eat it. You can add barley straw bales to help get rid of it. Microbe-Lift PL works too and won't hurt your fish or plants. I have also dyed a pond black, waited three months and the blanket weed was gone. If you feed your fish, you are also feeding the algae. If you have koi, think about changing to goldfish, so you don't have to feed them.

Tuesday, May 01, 2007

Spring is leaving

Spring just got to New Orleans and it's leaving already. My garden that was at its peak a few days ago now looks as if goats ate it. I have snaps to pull and compost, petunias that are melting in the heat. My bog garden is growing nicely; it loves the heat. Pictures as soon as some of those baby plants can be seen a bit better. We are so far down on rain this year, that I have to water my bog garden. Something is dreadfully wrong with that picture.

Ponds are turning green all over the South. String algae or blanketweed are taking over ponds that are just now waking up. I have found that having enough anacharis and about half the pond covered will take care of regular green water. String algae or blanketweed need more help. I use Microbe-lift PL and it works just fine. First you must get as much of the stringy stuff out and then use the Microbe-Lift PL according to the directions on the bottle. Using a toilet brush really works well to get existing string algae out of your pond.