I have a Koi Pond and the Algae gets pretty bad. Any way to keep this to a minimum?
I would highly recommend to having in place some live plants that soak up the excess nutrients in the water column, which will prevent from algae growing. That's why in many ponds, you will see various semi (or fully) aquatic plants in order to combat algae from taking over. Another method is to add in various powerheads to make sure that the water flow isn't stall somewhere, which will slowly prevent algae from growing and will likely cause for it to grow in the water column (which other natural bugs or insects will eat).
Limiting algae is all about balance. Do you have too many fish in the pond? Are you overfeeding them?
Also think about getting a biological filter. Establish a good plant to fish ratio, and get enough of (and the correct) aquatic plants. So you're talking surface plants for shade and floaters and underwater plants to remove excess nutrients.
I have a cousin in Virginia with a koi pond, and he swears by this stuff for keeping algae at bay, so maybe check that out too: http://www.watergarden.org/Algaway-5-
Hope this helps.