Aquateck Lotus Bio Master 12000 Pond Filter

Lotus Bio Master 12000 — biological and mechanical pond filter

The Lotus Bio Master 12000 is a gravity-return box filter for a pond system with a separate circulation pump. Oasis lists the 12000 as catalogue code AQ009. Water enters the filter, passes through graded mechanical foams and then through Flocor biological media before returning to the pond. This is the filter body and its media, not a pump-and-filter kit and not a UV clarifier. If your pond needs ultraviolet green-water control, plan a compatible pond UV clarifier separately.

Which pond is the 12000 suited to?

The Lotus comparison information published with the Bio Master range distinguishes low and heavier fish loads. For the 12000, it gives up to 12,000 litres at the lower stocking level and up to 9,000 litres at the higher level, with an optimum flow of around 4,500 litres per hour. These figures are a starting point for a correctly circulated, maintained pond, not a guarantee for any number of koi. A heavily fed koi pond can produce more waste than an ornamental pond of the same volume. When you are close to a limit, choose a stronger filtration layout or ask us to check the fish load, pump and return route together.

The number 12000 refers to the range model; it does not mean that every 12,000-litre fish pond can be run at any pump speed. Aim to deliver the intended flow through the real installation. The pump’s headline flow is usually measured without the losses caused by pipe length, bends, lifts and equipment. Compare the pump’s flow curve with the finished plumbing. A very powerful pump that overloads a gravity-return box can cause the water level to rise or the overflow to run before the foams have had a fair chance to do their job.

How the two filtration stages work

The mechanical stage uses profiled foams of different grades. Coarser material catches larger particles first; the later layers capture progressively smaller suspended waste. On the 12000, the green, white and blue grades are shown in Lotus range literature and in photographs of the exact model. Keep them in the manufacturer’s water-flow order when servicing. If fine foam is placed first, it can block prematurely and push water toward the overflow. Do not confuse this filter with a Green Genie: the Bio Master 12000 does not contain the Green Genie’s built-in UV unit.

Below the foams is Flocor biological media. Its purpose is to provide surface for bacteria that convert ammonia from fish waste and decomposing material through nitrite to nitrate. That biological process depends on a continuous supply of oxygenated pond water. Run the filtration continuously when it is supporting fish, and allow time for a new bio-stage to mature. Pondkeeper’s installation guidance suggests roughly three to six weeks for bacterial establishment; actual time depends on temperature and pond conditions. Test ammonia and nitrite during start-up rather than assuming that clear-looking water is chemically safe.

Dimensions and connections to plan around

• Product: Lotus Aquateck Bio Master 12000 gravity-return pond filter.
• Oasis supplier reference: AQ009. Pondkeeper’s retail product reference: LOTBIO12000.
• Mechanical stage: graded profiled filter foams.
• Biological stage: Flocor media.
• Approximate outside dimensions: 69 × 49 × 37cm (length × width × height).
• Outlet: 2 inches, according to the exact 12000 retail specification.
• Comparison-chart optimum flow: approximately 4,500L/h.
• Published low-stock pond figure: up to 12,000L; higher-stock figure: up to 9,000L.
• External pump and any UV clarifier: select separately.

Check the inlet fitting supplied with the current production batch and the hose diameter required before ordering pipework. A 2-inch outlet should have a free-draining path back to the pond or waterfall with a suitable gradient. Do not restrict the gravity return with a narrow hose simply because the pump inlet uses a smaller fitting. Build the base firmly and level so the filter does not twist once it is holding water and media.

Positioning and maintenance access

Place the filter above the pond-water level so the outlet can return water by gravity. It may be partly hidden, but do not bury the lid or block access to the foams, connections and overflow. Leave space to lift the lid and remove media without dismantling the whole installation. Check that a pump stopping will not create an unwanted siphon, and route any waste or overflow water to a safe place. Follow the maker’s installation instructions for the final fittings, level and connection layout.

When water starts using the overflow route, inspect the foams: this can be a sign that they need cleaning. Remove the foam grades individually and rinse them gently in a container of water taken from the pond. Chlorinated tap water can damage the useful bacteria living on the media. Refit each layer in its original order and orientation while still damp. If a foam has permanently collapsed, torn or no longer holds its shape, replace the correct grade rather than stuffing in an ill-fitting sheet that allows water to bypass it.

Flocor is not a disposable pad to replace at every service. If silt has built up in the lower chamber, keep the media wet in pond water while cleaning the box, then return it promptly. Avoid cleaning every biological surface at once unless there is a specific fault to address. After maintenance, verify that the water returns freely and the pond pump has not run dry. A log of foam cleaning, water tests and flow changes helps distinguish seasonal debris from a fault.

Build a complete working system

The filter needs an appropriately sized pond pump and correctly sized hose or pipe. If green water is a problem, consider a separate UV stage; biological filtration and UV treatment solve different problems. Compare other pond filters when the pond is near the published stocking or flow figures. Ensure the outlet, fittings and maintenance space work in your particular garden before buying on the model name alone.

Common questions

Does the 12000 include a UV light? No. The Bio Master is a mechanical and biological filter. A UV clarifier is separate if required for your pond.

Does it come with a pump? No pump performance is built into the box-filter rating. Choose a circulation pump for the required installed flow, accounting for the actual pipework and lift.

Can I wash the foams under a tap? For routine cleaning on a stocked pond, use removed pond water and preserve the biological media. This is gentler on the established bacteria than a full chlorinated-water wash.