Same here, the tadpoles left & the string algae has taken over. It's to the point it's breaking off (I'm assuming that's what's going on) & floating all over the top, I have to scoop/skim it off daily it seems.
I'm not even going to talk about the fall & how often I have to pull it off of there (or it seems).

As barley straw decomposes it will release a compound that will inhibit string algae growth. It's too late for that this year though, It needs to be put in early in the season so it will have a chance to begin decomposition. Put it on the list for pond start up next spring.

I've heard that hydrogen peroxide will also control it, though I have no experience with using it. Get advise from someone who has used it before taking my word for it.

Otherwise, you can always twirl (it around a stick) and hurl it. It makes a good compost!

Good Luck

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Barley straw releases hydrogen peroxide. You can add hydrogen peroxide to your pond, it is safe for your fish your plants, and your biofilter (in reasonable doses) and will kill the string algae if you use enough. I don't recall the dose of 3% solution, I've used sodium percarbonate in the past at 1# per 1000 gallons. A corresponding dose would be 5 quarts of 3% / 1000 gallons, but daily doses of 1 quart per 1000 for several days might do the trick and let you see how things are going. The biggest problem, it appears to me, is that the dead algae release their nutrients for the next flush of algae. But it will look beautiful for a week or two!

A pond in balance is a terrarium.

Snails eat dead matter and secrete it in a way that plants can use it. Bacteria decomposes dead matter and convert it into a substance that plants can use.

Lilies and Azolla caroliniana create shade that prevents algae. Barley straw releases chemicals that prevent algae. Plants consume the nutrients that cause algae.

Fish eat insect eggs preventing the pond from becoming an incubator for insects.

The fish create nutrients. The plants utilize the nutrients. The more food you put in the denser the fish population the more nutrients you get and the more out of balance the pond becomes. Less food, less fish and more balance.

Oxygenator plants such as anacharis add oxygen to the water so the fish can survive.

The problem comes when there is a fish overload and you lose your plants. In this case you need two ponds, one for the plants the fish would devastate and one for the fish and the plants they don't eat. Since I have Golden Shinner minnows I don't have this problem. My pond has no filter, no UV, and no problems.

I have had the same problem with string algae for three years. the stream and pond are in full sun all day which I think is part of the problem... I have a biological filter, UV sterilizer, and a bead filter. The water is clear...just have string algae. It goes in cycles. I have added the barley straw extract, have a ton of plants, do the beneficial bacteria thing and still have these cycles. I've even done the green clean treatment and like anything else, it stays clear for a time then it's back with a vengeance. So, I have decided on acceptance. In the summer months I do weekly 10% water changes, have lots of aeration for my fish (airstones and a fountain) and as I said above add the bacteria weekly. Everybody in the pond is good so far. So the answer for me?...acceptance...

Cindy, it appears some posts are missing. Why would you add bacteria weekly? How big is you pond?
Yng gdner, your main problem seems to be maintaining consistant water quality. Do you test the water? It sounds like you may be overfeeding the fish which would lead to more nutriants in the water to feed the algae. Sandy

Get rid of your string algae and you will end up with pea soup algae and be much more unhappy.

Algae is normal in ponds.

The only way to keep it out completely is to treat them like a swimming pool with chlorine. However, then you have a swimming pool and not a pond.

Healthy ponds are not sterile.

Use a toilet brush and twirl it out if it gets too bothersome to you but be happy that you have string and not pea soup. String algae won't hurt fish or plants.

Most people do over feed their fish and most people have too many too. Both encourage algae.

I am also having problems with string algae. I was thinking about getting some Black Japanese Trapdoor snails. I heard they also help control pea soup algae. I was wondering if anyone had any thoughts on this?

I doubt they do anything for pea soup algae. I bought Trapdoor Snail 2 different times. I only have 1 left that I know of. Maybe not enough algae for them to survive. Actually I don't think that is the reason. Sometimes I wonder if the fish eat them. But you need lots of them, the bigger the pond area the more you need. I have jillions of other kind of snails mostly in the bog filter, there's more stuff to eat there. Glenda

I'll start with a brief explanation of string algae then I'll get to how to remove it. String algae is mostly found crowding your marginal plants, in the stream bed, and sometimes in bad cases it will grow on the bottom of your pond. String algae is really hard to pull out of a pond because it clings to rocks, plants and everything else (well, not the fish because they are slippery).

When removing it, be sure to never rip string algae out because this will cause the algae spores to detach from the algae and encourage future growth. Either hold the algae and cut it out with scissors, or twirl around a stick to grab all of the algae.

Here is a link that might be useful: Algae answers

Maybe you have too many fishes in your pond. Fish waste helps string algae grow. Try to reduce your fish and see if it help. Adding bacteria to your pond also help stunt algae growth. Be careful when using algeacides, though, as it will be harmful to your plants and fish. The link below pretty sums up my strategy.

Here is a link that might be useful: The Pond Blog: All About String Algae