Bioforce 2500... and 6000.
The 6000 pump you can either add a skimmer (additional point where it sucks) or use the blanking plate and you can even set the rate using the valve (acts like a mixer when using two inputs).
Feeding.. a slightly larger canister!!! (from 4500 size to 9000 size) that has a switchable waste gate & agitator and larger UVC built in.
Added the old media at the bottom as it has bacteria
The filter material is based on cubes rather than the circular flat filter pads. I've added some pond bacteria balls to help establish the filter.
Agitator arms resisting arms to churn the media and the UV bulb tube 24W to cope with the throughput:
Installed in position - I removed the recent 15W UVC and the electro gadget.. this thing takes the entire space!
Flow rate? Well have a look:
I think about 2x or even 3x previous rate.
The pond is ~4m x 2m x 1m (avg depth). It has koi (ghost and a couple of normal) hence you need twice the rate and poop extraction because they literally poop.. and poop.. that's 8000 litres.
The pump is 6000 l/h max, 3.5m head max.. so way way more oomph. The canister is sized for 9000l with a full stock of fish (i.e. koi), or 18000l with few/non-koi.... So the pump is sized about right for koi, and the filter is now actually slightly over sized for koi which is a good position to be in.