Razoola,
I'm far from being an expert in this area, but I really think that your pond will clear on its own if it is from the clay.
When I look at your "old pictures" the water looks absolutely perfect. I'm assuming it is brown from the tannin produced by tree roots and tree leaves around the pond.
The photos are beautiful, and your place looks extremely inviting.
It is possible that the carp and koi are stirring it up. But, if the water was relatively clear, except for algae and tannin before the cleaning, I doubt that is the case.
I think that your pond is acting like a recently formed or recently dug pond. There are a lot of extremely fine clay particles suspended in the water. It will just take time to let this clay settle out.
I don't know what part of Finland you are in, but I can only assume your pond will start to ice-over sometime in the next two to three months. I know it is a long time to wait, but ice and cold have a way of really settling a pond. I would estimate that by springtime when the ice melts, your pond will be clear of the clay.
You may have to "enjoy" the brown water if it is from tannin. From the older photos, it looks like you've had good plant growth in the pond. The plants will help take up nutrients, thus control algae formation.
Lastly, where does your lampi vesi come from? Is it above ground runoff, a spring, or some other source like a pieni puro? Is it bringing impurities or too many nutrients?
Ystävällisin terveisin,
Monnipoika
