Green water was yesterday

We have created us one about 4000 liters of pond. The pond was about 10 days "run" with plants, without fish. The water was crystal clear up to this point. After the fish have moved in was the water from day to day dull and greenish. Our built-up pump was ok and also strong enough because it could not be. Even too much food or other dirt was not an issue. The water was not clear.

After searching the internet we bought these UV filters of Berlan. The installation has been easy. After only 24 hours the water was much clearer. After 72h the water was crystal clear then, you could see 2m to the ground. For us, the filter has absolutely worth it, especially one benötig no chemical or other means. Simply top. Clear recommendation!