Can you recommend a motor and a UV light for the bog filter of this pond?

[Jaguar.cic]

Appreciate your ideas on building a bog filter. Pond is almost built for some koi gonna be be received soon, and plan to build the bog on one side of the pond like I saw in a picture in Google. I've attached the building pond's photos and also the type of bog filter I saw in Google is in the last picture.

Pond's length = 12ft,
width=9ft
depth = 4ft
Capacity = about 12000 litres
Fish to stock = koi

Suggestions about motor, where is better to put it, whether it should be external or submersible, where to put, inside or outside the bog and what kinda UV light is suitable and where is better to fix it, are highly appreciated.


Thank you very much!

 

[jovibuilt]

I used a 36watt uv light in line before the bog on my koi pond. My pond is 10ft x 10ft and 4ft deep. I am overstocked and my bog filter is worked well for 2 years. You can see the bog here before I planted it.

 

[Jaguar.cic]

I used a 36watt uv light in line before the bog on my koi pond. My pond is 10ft x 10ft and 4ft deep. I am overstocked and my bog filter is worked well for 2 years. You can see the bog here before I planted it.

Can you please explain me a little how you put the UV light in line with a photo please. That would be a big help. Does 36 watt UV do the job for you? What's the speed of your pump for UV. Do you use a separate pump for big?