Question
I have a pond that is approximate. 500 gallons.  I have 3 Koi and 3 Gold fish.  I have a couple questions.  1) My pond was clear after the winter, then 3 weeks ago the pollen got bad and now the water is VERY murky, I installed a new filter (AN265 Fish Mate Pressurized 9 Watt UV Bio Pond Filter 1000) is there anything else I should do and is this filter the correct one for me to use? 2) my fish very rarely come up to the top to be seen, and when they do, they take off if you move around the pond.  It has a waterfall that the filter feeds into, and then I have another pump in a filter at the bottom of the pond that feeds a spitting Gnome that spits into the middle of the pond for oxygen.  any suggestions would be great for anything I can change or do differently.  Will the spitter keep them from coming up (scare them) should I switch back to a fountain?

Answer
Dear Michael,
Thank you for your question.
500 gallons is I think approximate 2000 liters and A fairly small pond for koi.
And A small pond if often harder to keep clean as A large one.
I think best way is to filter and use A UV lamp.
This with A pump not larger then approximate  500 to 1000 liters depending on the ammount of 90?turns and the height on witch the water returns to the pond.
Also due to the small pond the water can heat and get cold easy and stresses koi.
To keep koi less stressed you need to make an area where there is lots of shade as they then can hide. Also keep movements low if possible at first and build up from that point.
Hope this helps and please do not hesitate to contact me for further assistance.

Good luck and happy pondkeeping!
Raf