Hi Steve
I have an oasis clear pond 25000 with 25w uv being served by a 8000ltr pump, at the other end i have a green to clean 12000 with 16w uv this is supplied by a 4500ltr pump. As for food i am using a blue pellet type that I picked up form world of water, i only ever feed until the fish lose interest so there is not waste. As for water change being new to koi keeping I am finding
out new things all the time, I did a 10% change last week and used tap water which i know isnt ideal. All fish seem really healthy and I know that the filters arent top of the range etc but funds are limited. | 
