Guidance Notes For Setting Up & Maintaining Cloverleaf Fluidised Bed Filters:

1/ For stability purposes all Cloverleaf FB’s should be screw fixed at the base (via the circular base plate) into a stable backing. A 450mm square (18”) thick precast concrete paving slab is an ideal medium for this, or alternatively one of the large 600mm square (24") heavy duty timber decking panels as found in numerous garden centres. The use of rigid pipework in lieu of flexible pipes can also contribute much to increasing stability. Using a builder’s spirit level can be useful for obtaining a true vertical, but it not vital for those with a very keen eye.

2/ The pump sizes as recommended elsewhere (for M25, M70 & M140) should only be regarded as a guide, when parameters such as distance from the FB to the filter/pump – length of pipe – number of bends etc, will all have an influence on actual pump rates. (For further guidance the compact "Laguna 2000 Powerjet" 810gph is very powerful when connected to an M70, to the point that the valve on the FB barely needs opening)

3/ For the reason noted above the FB should be located as close as possible to the main filter. All associated pipework should ideally be 1.5” diameter (38mm). Note however that the M25, M70, & M140 have a standard 50mm (standard 2") plastic "T" connector at the top of the unit which forms a vertical vent and horizontal outlet connection for the rigid plastic gravity return pipe (2"). Please refer to the photo link noted below for a visual example of the 2 inch pipe being returned into the top of a multi bay filter.

4/ It should be appreciated that although relatively small GPH flows are applicable through the FB’s a larger sized pressure type pump is required in order that the silica sand can initially be pushed into full suspension. An example of this could well be that a desired and operational flow through the FB of say 250gph may possibly need a 500gph pump to lift the sand to start with.

5/ When setting up the FB for the first time it is recommended that the side valve (on the FB) is only barely cracked open, and thereafter should be opened very slowly to the point that all the silica sand is in full suspension. Immediately this happens it should be possible to throttle back (close the valve a little) without the sand falling out of suspension. Once this is achieved the setup is complete. Some due care is needed during these procedures when too much pressure or flow rate will blast all the sand out of the top vent pipe. When in suspension the top level of the silica medium should not exceed the height of the transparent acrylic section of the FB tower. Ideally 10mm to 20mm below is fine. (See Photo link below)

As a guide the volume of the silica sand when in suspension could be visually expressed as increasing in volume by around 120% - and it is the fact that each grain of silica medium is surrounding by its own free area of water which thereby allows each grain of the media to be colonised by beneficial bacteria on all sides.

6/ As the silica sand in the FB becomes mature & colonised with beneficial bacteria it will as a result become heavier - basically doubling in weight. As a consequence of this there will be periodical times when the side valve needs to be opened slightly more in order to sustain maximum suspension of the sand. Monitoring this situation at frequent intervals is no more than good pond management. It is worthy of note that on day one of setting up the FB the gph flow will not appear that great - simply because not much flow is needed to get the "new" silici sand medium into suspension. This will improve/increase over time, as the medium becomes colonised and heavier - thus requiring more pressure/flow to retain the desired level of lift.

7/ Large beneficial bacteria colonies demand high levels of saturated oxygen for their best development, and in instances where the FB is fed from a pump in the settlement area of say a Genesis or CL range filter, then the wise hobbyist might consider adding some airstones into the main filter transfer ports – in order that the FB is oxygen rich. (See webpage covering aeration of filters).

8/ Over the course of time some of the Cloverleaf silica media will disappear, and thus need replacing. With this in mind when first setting up the Fluidised Bed the silica sand should be duly added, and its top level permanently marked on the clear acrylic tower before turning on the pump. Thereafter any loss can be established by switching off the pump, letting the media settle, and relating the sand level to the marked datum line. Any topping up should ONLY be made using Cloverleaf's unique media. Following such additions re-adjustment of the flow will again be required (all as described above). Minor re-balancing might also be required each time the pump is turned off, but naturally this is a very rapid procedure. (See Photo link below)

9/ When connecting a pumped supply FB (M25, M70, M140) into a pumped Cloverleaf Multi Bay Filter it will be necessary to cut a  hole/cutout in the main filter lid (see diagram drawings for flow and return - see also photographs via link below). This exercise is very easy in the timber slatted lids applicable to the “Genesis” range – but will require the use of a tenon saw & Stanley knife for the heavy gauge plastic lids on the CL Professional range. (When installing the Cloverleaf pressurised M25P, M70P, or M140P, no modification to the lids is required – assuming the setup is as defined on the diagram drawings).

10/ All Cloverleaf retailers/distributors are qualified to provide good technical advice to the hobbyist, however where required further support is available (in the UK) via the Cloverleaf Helpline 01277 366002 – or naturally via email.