According to Stapeley Water Garden's advisors, a UV unit should have an effect on existing green water within three weeks. If not, then you should check that the flow rate of water through the unit matches the recommended rate and can deal with the pond's volume.

Manufacturers tend to assume that a pond contains a few small fish plus plenty of plants, so you need to fit a larger UV unit than often recommended (or combine a couple) to deal with the specific demands of a Koi pond.

Comments

  1 terry bonner    12 Aug 2010 16.54.10

  2 Alec and Val    12 Aug 2010 18.28.10