Hi Lobster
Thanks for the nice comments
First of all, the only thing Im sure about - is not making the same mistake as last time. I will not buy more fish before the pond(s) are ready. That will take time (years)...
What Im gonna do fist, is turn the area around the mud pond into a nice park. Today it impossible to spend time there because of all the threes and bushes etc. Today its dark, difficult to move, and the bushes stings you. When the park is finished next year, I can start thinking about what to do with the pond(s).
The mud pond will be needing more air and water movement. The koi added last year survived the winter this year. I do believe that one reason is the new air pump I added last year. It kept an open area all winter. I believe even during the summer I should be adding air to make water movement. My teori is that it will help fighting the alge-problems. If I can keep the few koi alive, I don't HAVE TO add more fish. Of course I would like to add more fish, but i DONT HAVE to. I can even consider adding Gold fish, but my preferred choice is koi.
What I want to do after making the "park", is build a concrete pond. I have all the equipments, so it will not be that expensive. I can even build some sort of cover, to keep the water warm during the winter. What I haven't decided yet, is where to build it. In my garden close to my house, or in the "park"? If I choose to build it in the "park", Im considering connecting it to the mud pond. In teori the koi will seek for warmer water and come back into the concrete pond. Then I can close "the door" before it gets to cold.