A mixture of floating oxygenators and plants on the shelves and edge of the pond should help the water in the new pond to become balanced.

You're bound to get the usual pea-soup algal bloom at first, which will go once the excess nutrients are exhausted, but the murk due to suspended clay particles may remain a problem for some while. Be patient, and if the problem doesn't resolve itself, choose one of the products sold for clearing turbid water.

At the edge of the pond, choose plants that grow in neat clumps (e.g. such as marsh marigolds, Mimulus, water avens, Primula), or spread with a shallow rooting system (e.g. creeping Jenny). Avoid reeds, sedges, watermint, yellow flag, cotton grass, bog bean and other plants that we associate with natural pools and lakes because the roots are invasive and can easily damage the clay lining.