Question
Hello Robyn,

My wife and I bought a house about 3-4 months ago that has a fairly large pond in the back yard.  Neither of us have any experience with ponds and other than cleaning the filter/pump and skimming out some algae I really don't know what else to do to keep things running smoothly.  The pond is about 12'x8' oval and has a tiered bottom down to 4' in the center.  It has a continuously running pump that filters the water and sends it up to a bog above the pond.  The water flows down about a 6' to 7' rocky water fall that's at a 10?to 15?angle back into the pond.  The water has seemed clear all summer and we can see our 2 fish (bigger Koi and smaller goldfish) very easily.  The only thing I have to keep on top of is algae growth on the rocks.  I spend about 20-30 minutes 2-3 times a week raking it off the rocks and cleaning out the water fall area.  Is some algea normal or should we be adding some chemicals of some type to slow the growth?  Also we want to add some more fish.  I was thinking about 4-5 more Koi, starting them small and letting them grow.  We feed them Koi food.  Little sticks that expand in the water and we have 2 good sized water lillys and other plants around the pond.  Are 4-5 more Koi too many for our sized pond?  

One other thing.  We live north of Seattle and it doesn't get really cold through the winters here.  What steps should we take to prepare the pond for the cooler/colder months?  Thanks for any tips you can give us.

Answer
Check out my site on ponds at http://www.fishpondinfo.com to get started on your pond education.

It sounds like you have a good pond and setup.  For algae information, see http://www.fishpondinfo.com/plants/algae2.htm
Is the algae long and hairy or short?  Short algae is good; don't clean it off.  Hair algae can be a pain but I usually don't bother to remove it when it crops up which isn't too often.  You should not be spending that much time cleaning algae.  I spend maybe 30 minutes a YEAR cleaning algae from my ponds.  

Your pond is probably about 1000 gallons.  Since it has various depths, that's just a guess.  Experts say to have one koi in 1000 gallons and 100 gallons for each additional. So, you really don't want more than a few koi in there.  You can certainly add a few more.

For winterizing information, see http://www.fishpondinfo.com/winter.htm
Your pond is nice and deep so the fish should overwinter just fine.

I could tell you a lot more but I'm pressed for time but feel free to ask more specific questions.

Good luck!