Filtreau Excellent Combi Drum 50/70 – Gravity Fed

Filtreau Excellent Combi Drum 50/70 – Gravity Fed

A larger gravity-fed system with automatic drum cleaning

The Excellent Combi 50/70 Gravity is designed for a larger pond whose filtration needs have moved beyond the smaller combi models. Its 650 mm-diameter drum and six 110 mm inlets give the system scope to handle several bottom-drain and skimmer lines, with up to 70,000 litres/hour of water flow.

The filter combines mechanical separation, biological chambers and 80W high-output UV-C in a 1,825 × 1,117 mm footprint. It is a substantial piece of equipment, but one coordinated unit can be easier to plan than several separate treatment housings joined by extra pipework.

Removing waste before it accumulates

The drum screen retains solids at 120 microns. When flow through the loaded screen becomes restricted, the level sensor starts a rinse: the internal pressure-cleaning pump feeds the spray bar and the motor rotates the drum. Dirty rinse water leaves through the waste route.

This helps prevent the biological section from becoming a settlement chamber. It does not remove the need to inspect the waste channel and nozzles, or to deal with string algae and bulky material that can obstruct pipework before reaching the drum.

A biological setup sized for feeding load

The optional media arrangement is 200 litres of Hel-X with 3 m² of Japanese matting. Treat those as media choices within a designed system, not an instant guarantee of the maximum koi load. Keep the moving-media section aerated and leave enough free space for the media to circulate.

For loose matting, choose our high-quality Japanese matting sheets in the quantity you need. One sheet measures 1.2 × 1 m; two provide 2.4 m² before cutting, which is less than the listed 3 m² arrangement. They are useful uncut material for the fixed-media section, not a complete pre-shaped cartridge kit. The air pump is separate and should be selected for its output at working depth.

New biological media needs time to mature. During commissioning, measure ammonia and nitrite and build feeding gradually. Keeping a large koi pond clear is only half the job; the filter also needs sufficient mature biological capacity for the food going into the water.

Planning the branches and returns

Six inlet branches offer flexibility, but each needs a sensible pipe route and access to its isolation valve. A poorly balanced bottom-drain and skimmer manifold can leave one part of the pond under-served even while the total pump output looks impressive.

Compare the pump-fed 50/70 if the filter will sit above the pond and receive pumped dirty water. The 50/65 Inline XL is another useful comparison where a narrower, longer body fits the space better.

Key dimensions and performance limits

Looking after the system

Keep space for lid access, UV servicing and waste-pipe clearance around the supported, level base. Maximum flow is an upper limit, not the recommended permanent setting for every installation. Watch the operating water levels as pump output changes and allow for increased resistance as the screen loads.

The matching 50/70 trickle filter can add a separate biological stage, but its own flow limit must be respected. Follow the Excellent manual for safe cleaning and servicing of the drum and UV equipment.

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• View the full Filtreau range
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• Read our drum filter guide
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• Choose a variable pond pump
• Choose a Charles Austen air pump
• Pressure pipe, valves and fittings
• View Filtreau UV-C units
• Find replacement UV lamps and quartz sleeves
• Filtreau Excellent Mountain Tree Combi Drum 50/70 – Gravity Fed