I have 3 large metal stock tanks. Over the years I have never had any problems with string algae until last summer. My oldest stock tank that is over 20 years old started growing lots of string algae. That sort of surprised me since it had never happened before? I have often wondered if the zinc in the metal prevented the growth of the string algae in some way? Neither of my other stock tanks had a problem with algae at all. However, I have changed this older tank somewhat. A couple of years back, it developed some small holes in the bottom of it. So I painted the bottom with swamp cooler tar, completely covering the metal. So a lot of the surface metal was covered over and there was less zinc to get into the water. Now I don't know if it was the zinc or not, but something is preventing the algae grow in the two newer stock tanks. Have any of you that have metal stock tanks noticed not having a problem with string algae or do you have a problem with it?

I have only had limited success with barley of any kind. I did have some luck with hydrogen peroxide, but I'm a little squeamish about using it and it is a bit controversial. Some people get very hostile about it, but I must say the algae disappeared pretty quickly after using it. I used one bottle per 500 gallons. The barley releases hydrogen peroxide as it decomposes, but it must be in smaller amounts. I ended up erecting one of those picnic tents over the pond to shade it from the sun. This has been the only thing that has really worked for me, other than the multitudes of tadpoles chowing down on it, LOL. I started looking at the advertisment flyers for the sporting goods stores, and found one cheap. This may not be an option for you, but here's a pic so you can see what it looked like. I used it during the hottest part of the summer. I have a koi pond "hybrid", rather than an actual watergarden. All my plants are in bog pockets at the pond's edge, but I usually put one Blue Beauty water lily in a sunny corner of the pond because they're so gorgeous.

She spread a sheet of some string algae out on a flat rock and determined that dried it has a resistance to tear and puncture somewhere between toilet paper and cheap paper towels. No use for this observation yet. She twisted some into a twine and determined that if it allowed to dry somewhat, but not entirely, it can be used for macrame. She does not have enough to do a complete experiment yet. I find it curious that this one developed in cold water. We did not see it last summer. Now that the water temperature is getting to 50F most days I don't see much of it anymore.

I suspect that they don't specifically eat the string algae. In my pond they will go nuts if I flick in a snail or two. If there's string algae in the way too bad!!! You'd think I was serving them escargot - without the garlic butter!!! ---David