Cloudy water

[Chris71]

Hi
I have recently built a pond in my garden.I've added some oxygenated pond weed, a filter and left it to run for four weeks, and the water was crystal clear. A few days ago I purchased some koi, and the sales assistant advised me to add some anti-parasite & fungus liquid. Overnight the water has turned cloudy, and the pond sides and weed are covered in fungus, any advice to the cause would be much appreciated.

 

[sissy]

all you would have needed is a uv and koi produce a lot of waste and get really big .If it is city water that could be it

 

[Chris71]

I have a uv, and the water has been in the pond for four weeks.

 

[JohnHuff]

What does the fungus look like? What size is your pond and what filter do you have? The purpose of sales assistants at stores is to sell stuff.