FAQ’s – misunderstandings, incorrect assumptions and lots more


Many still assume and state to others that Eric units are ‘multi-chamber filters’ – they are NOT.

All Eric units are simply single-chamber boxes.

Q. Others still ask as to how many drains can be taken into each Eric unit.

A. One Drain to One Eric to One pump. (This incidentally should be applied to ALL filter systems as it’s simply impossible to send multiple lines by gravity into a common box and get perfectly equal flow rates from all the lines.)

Q. ‘The line from my bottom drain is 4” diameter but do I really need a 4” line to waste’?

A. It’s absolutely paramount that the waste line is also 4” bore in order for the discharge to have the maximum cleansing effect.

In cases where a 4” line cannot be taken to your sewer then a discharge box or a soak-away should be considered.

Q. ‘Why are there holes now drilled into the top and bottom of the brush box’?

A. These are finger holes, which allow the brush box to be easily raised slightly above the floor of the unit when an actual discharge is being carried out; this ensures that anything unwanted right on the base of the box is also removed to waste.

Q. ‘How do I clean the brush box’?

A. The brush box is generally self-cleaning by the force and weight of water from the bio section behind it during a normal discharge. However should some leaves and twigs entering from the bottom drain still remain attached, then whilst the filter is empty, they can easily be rinsed off quickly with a garden hose.

Q. ‘How can I purge the pipeline from the bottom drain”?

A. Your pipeline is purged every time the filter is re-filled. However, if you wish to check it’s absolutely clear – when re-filling then do so with the standpipe removed from the waste and the incoming water will enter the unit and then go directly to waste.

Q. ‘When do the cartridge blocks need changing or cleaning’?

A. They never need changing and rarely need cleaning but it is recommended to lift them out annually and rinse them off quickly with a garden hose.

Q. ‘Will the filter system block when I go on holiday’?

A. Eric units cannot block in normal running but if they are left unattended for some time they will need to be flushed to waste several times to clean them properly and bring them back to new.

Q. ‘Can the latest standpipe still be used as an overflow also’?

A. Unfortunately it can’t but an overflow can be fitted at extra cost when ordering the unit. On the plus side, the new standpipe is so much easier to use’.

Q. ‘I’m on a water meter, how much extra water will I use if I buy an Eric filter’?

A. Unless I’m very much mistaken you will not use any EXTRA water, in fact you should use LESS water.

An Eric Four running a 4,500-gallon pond will dump 114 gallons – that’s a 2.5% water change, which is the minimum daily change on that volume for any self-respecting Koi pond.

An Eric Three running a 3,250-gallon pond will dump 84 gallons – that’s also a 2.5% water change and an Eric Two on a 1,700-gallon pond will dump 53 gallons – that’s a 3% water change.

But remember, this can all be done in minutes AND you don’t need to wait for top-up AND you’ll have a brand new filter at the end of it all!

Q. ‘What are the recommended flow-rates for Eric filters’?

A. The total volume of the pond in question should pass through the filter every 2 to 2.5 hours in order to allow sufficient dwell time on the biological surfaces. In truth only a gentle flow-rate is required which makes running costs very economical.

Q. How much aeration should be added to Eric filters.

A. For the E4 – 120lpm; for the E3 – 80lpm; for the E2 & E2P – 60lpm.

Q. ‘How often should Eric filters be discharged’?

A. The honest answer here is DAILY, although few stick to this good advice.

There are several reasons as to why this should be carried out daily and bearing in mind how easily and quickly it can all be done these following reasons should make good sense.

Firstly, all fishponds benefit significantly from regular partial water changes.

The most obvious place to throw wastewater from the system is the lavatory or in this case the Eric filter unit.

Bearing in mind the very small volume of water in each model then that would be the minimum amount to throw away and then top up very slowly, over the next 24 hours, with a trickle of new water from the mains.

In truth the daily water thrown away on a total discharge of any Eric filter is only around 2% of the system’s total volume.

Secondly, the total discharge from any Eric unit is exactly that, namely the water in the mechanical stage and the water in the biological stage is all thrown to waste via the powerful suction of the open 4” diameter drain line which also backwashes the brush box at the same time.

Thirdly, (and only users know this to be a fact) – but providing the unit has a lid or is protected from garden debris and falling leaves, only very minute particles of debris coming from the pond drain will even pass the first row of brushes. It’s extremely rare that any pond debris enters the biological stages.

There will be more answers to this same question soon.

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