I bought the rush for my small koi pond because I liked the looks of it. I had no idea at the time that installing it in the pond would put and end to the string algae. I still use a UV filter for floating algae but the string variety has been completely eliminated. I've tried a second plant (other than the rush) along with the rush but it didn't survive. Perhaps the rush was too effective. Who knows.
Heron. Nasty birds who love fish, moles and anything else that can't escape their patient observation. As we're also subject to visits from black bears I set up a trail camera which, as it turned out, is equally effective at picking up a heron. First capture caught it approaching the pond and downing a mole. Like others, I keep a bird net in place. Works for the leaves as well as the herons.
Funny you mention that about string algae. Hubs and I noticed that we have not had any string algae in our pond this year. We thought perhaps it was because there is more shade on our pond. It also has not been as warm this summer as it normally is for us.
A follow up on pickerel rush and string algae. When my current plant matured, while basically resembling a rush when the long flower stems appeared from the plant base and not the leaves I looked in to what I really had. Turns out to be a thalia dealbata, a canna (lily) and not a rush. But, it works just as well as the rush so no complaints.