will putting pennies into goldfish pond help with Algae?

If you have fish the zinc in the pennies may be toxic as we just learned from poster "psa".:

http://garden.org/thread/view_...

Actually, the copper could hurt them, too.

While there are temporary cleaning and chemical measure you can use, filtration of fish wastes is the best long term solution. Options include :

electrical mechanical filters

submerged, floating, and marginal plants

nitrogen absorbers such as small straw bales

regular water changes with non-(or de-)chlorinated water.

My favorite is option 2, but option 1 is the easiest for most people. A combination of methods is often most effective.

Come join us in the Ponds and Water Gardening forum for more information, ideas, and advice:
http://garden.org/forums/view/...