I live in Mich and this summer set up a small pond ( about 150 - 175 gall ). I have some green hair algae and have asked about it and people say that this is normal to an extent. I was just reading a thread by fish guru on pond maintence. It is mentioned in there not to do a complete water change, so my question is what to do during the winter. I have planned on bringing in the fish & plants and emptying the water but I am now confused as to what to do with the water. Thanks in advance for any advise.