What filters and pump size for Gravity fed Koi Fish Pond?

[Millian]

I rent a house and it has a concrete Koi fish pond and what I believe is called a gravity fed filter system.

There is a vertical overflow pipe, which takes the water from the pond into the first sump (think that's the correct term). There are 3 of these ground level sumps next to one another and it appears the water moves from one to another when it gets a certain height and flows over the connecting walls.  I can see there is what appears to be small bio balls floating in each sump (about the size of half satang coin), but there's hardly any there.   

In the last sump there is pipe that come ups and out and connects into a large concreate pot which has what appears to be a bag of coral inside. I believe I need a pump that connects to this pipe to suck the water through the coral filter and then back into another pipe that flows into the Pond.

My questions are:

A. Do I just need bio balls in each of the 3 sumps and how many?  Do I need to fill each sump? That would seem to require 10000s of them!
B. The pond is approx. 2777 litres in volume, what size pump do I need to filter that amount each hour?



 

[Simple Jack]

Hey Millian.

 

You wan't something that can circulate the volume atleast five times an hour. 10000L/h would do. But more is better. Goodluck with the Koi ????

[worgeordie]

I just use the shade stuff, thats used to shade say orchids,

cannot think of real name, but its cheap, filters very well

and lasts a long time, easy to clean with hose pipe, you

can also get a finer one ,looks like mosquito net but is

made of plastic usually blue colour,use that in first 

sump,lot cheaper than other filter material and works.

You should be able to find in any market selling garden supplies.

regards worgeordie   P.S. whatever pump you use make

                                        sure  its earth properly,and unplug

                                        before doing any work in the pond.

Edited May 23, 2021 by worgeordie

[Millian]

Actually, taking a closer look , there are 4 of these ground level sumps next to one another and the water moves from 1st one to the 2nd when it gets a certain height and flows over the connecting walls. Then there is a higher wall that separates 2nd and 3rd sump, which flow via a submerged pipe. Then water moves from 3rd to 4th sump over a wall again.

 

In the last sump there the pipe that come ups and out and connects into the large concreate pot which has a bag of coral and oyster shells inside.

 

There is a 2nd pipe in this sump which takes the water back into the pond and optionally up for a waterfall across the back wall.
 

There is also 3rd pipe, which is t-shaped and also takes the water back into the pond using gravity.

I believe I need a pump on the pipe which connects to the coral filter to suck it through, but I'm not sure how it goes back into the pond, as this pot seems to missing an outlet pipe connecting back to the pond. Although there is a  hole at the top front, I presume it's just missing a pipe connecting it the pipe that feeds back into the pond/waterfall.

Where do I need to connect the pump to in this set up, any ideas?

I found a device at the bottom of one of the sumps connected to a thin pipe, any idea what this is?

Edited May 23, 2021 by Millian

[Millian]

33 minutes ago, Simple Jack said:

Hey Millian.

 

You wan't something that can circulate the volume atleast five times an hour. 10000L/h would do. But more is better. Goodluck with the Koi ????

I read I need to circulate the actual volume per hour, but x5 you say?

[Simple Jack]

4 hours ago, Millian said:

I read I need to circulate the actual volume per hour, but x5 you say?

Iv'e never kept a Koi pond. But i am a tropical salt water aquarium enthusiast.

 

My rule of thumb is normally 10x. Generally the greater the circulation rate. The more effective the filtration and aeration become.

Maybe someone who has experience with Koi can chime in. But i stick with my statement above.