Filter Upgrade – 3,500 Gallon Pond

This customers pond contained 3,500 gallons which was ran on a Nexus filter system with external UV.


Firstly the original filtration system was removed, filter pit excavated and a new larger concrete base poured.


With the new base poured and set, a Combi 35 went in place. With all retro fit jobs modifying pipework isn’t always simple and sometimes due to how pipework runs through pond walls etc. some pipework can’t be perfect. In this example the bottom drain pipework came out of the floor tightly in the corner of the filter pit. The bottom drain pipework had to be configured in such a way to bring it out and in-line with the combi. The same goes for the return pipework. The previous return pipework consisted of Flexi pipe going into the UV and returning back to the pond underwater.¬†Installing a submersible Amalgam UV into the Combi, the external UV was taken out of the system. The return pipework now simply goes from one end of the bio chamber, into the pump, and back to the pond underwater. All in PVC pressure pipe, not Flexi!

Finalising the air pump configuration, electrics and adding the media to the Combi. All was complete! The customer has plans for extending his filter bay and creating a cover for it to keep everything out of view.

Final specs:

3,500 gallons
QK35 Combi with Micro K1 Media
40w Amalgam UV
Aquaforte DM-Vario 20,000 Pump
Charles Austen Air Pump
1 x Pump fed Skimmer already in place which simply recirculates.



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