It also makes the pond more natural. Nonetheless, algae can cause a pondkeeper to break down in tears. It can be an ugly mess. It's hard to remember that it is a natural part of the process. There are many ways to control algae, but I've yet to find anything particularly effective except letting nature take its course.
New ponds are especially vulnerable while getting the plants going.
That's why I like reeds. They grow fast and have great filtering action. I have had absolutely no luck with electric filtering systems although over the years I've received e-mail from ponders with all sorts of creative filtering theories. Still, controlling algae is a balancing act. When all is in balance, the algae will also be in balance.