Upward Flow

This next example shows the UPWARD-FLOW design first employed in the early 1980’s and still the most used system today around the world in all its various manners and guises.

Some of these guises are pump-fed with gravity return; gravity-fed with pump return; surface side exit; surface central exit; surface trough exit; circular upward-flow patterns; multiple chamber units; aerated fluidised media systems and many other variations. Again, these relate to a body of water moving upwards in any given container/box.

The next illustration below shows a side off-take box with heavily aerated semi-buoyant plastic media media as opposed to fixed-position block media, this method is more commonly used in intensive fish farming applications.

The majority of heavily-aerated media particles still remain in the surrounding water completely untouched by the constant incoming supply that passes through the ‘invisible tube’ directly to the exit.

This leads to another very true fact, which is, as water rises uniformly through a suspended captive bed of inert surfaces (a filter media barrier), then this will supply ALL media surfaces with a constant flow rate of water – and it does just that, perfectly!

The very moment that water is allowed to overflow the top of the box by exit pipe or be sucked off the top of the box by pump then disaster results. This ‘disaster’ comes by the name of ‘tracking’ as displayed with the above animations. This is simply explained by the fact that incoming water to the box, either by gravity or by pump has impetus, motion, movement, force or current behind it – call it what you will.

This incoming, moving water has one idea in mind and that is to get to the point of exit at the top of the box, which also has equal movement – either by gravity or by suction.

As can be seen, this reduces the constant coverage of the media surfaces to a pitiful usage of only 15% of the surfaces contained within the box. In truth, the box may well be 85% smaller in dimensions for all the actual use it is.

The only way this problem can be resolved is to empty the entire box in order to find the stagnant water, and then throw it away – and as regularly as is possible. This however does not have any effect on the coverage of the biological surfaces within the box when re-started. Furthermore, by linking additional identical boxes together as ‘multi-chamber’ applications, this merely complicates the matter further and only increases the amount of stagnant water within the overall system accordingly.

The first of these systems were employed outside of Japan around the early 1980’s – almost 30 years ago, needless to say, thirty years of experience has resulted in being able to address these significant shortfalls today. As we all know, better designs will usually replace older less efficient ones in just about everything we use.

The trouble is that some other people listening or reading, actually believe them – some have even been seen to congratulate them! Let’s take a real example here of a system containing 20,000 gallons for ease of calculation purposes. By foolishly taking the 10% recommended by the guru, this requires a filter box or boxes that retain 2,000 gallons of the system’s water.

To give one idea of the box dimensions required to hold this volume it would be a perfect single cubic box with dimensions of just a touch over seven feet or, to give another example, a series of five, four feet cube boxes, linked together in order to hold the same amount of water. The task now is to get ALL the incoming water, at whatever flow rate is applied, to pass through AND OUT of these boxes constantly. From the illustrations already given, this is a pure impossibility and simply produces huge amounts of still, unmoving and stagnating areas of toxic water within the boxes that have no possible chance of passing on their contaminants to the bacteria waiting on the media surfaces.

Percentage figures such as these are spouted by those who have not one single idea as to how an efficient filter box needs to perform to the best capabilities of its maximum dimensions. One thing is certain, and that is we need to pass ALL incoming water over ALL biological surfaces as quickly as is reasonably possible and then get ALL of that same processed water the hell OUT of the box and AS RAPIDLY AS IS POSSIBLE because we need to make ALL available space for ALL the new incoming water!)

To summarise on the subject of ALL upward-flow boxes in ALL their guises and ALL of their multi-chambers, the truthful answer is the same for ALL.

PRESSURISED POND FILTRATION UNITS.

I think I have made my views extremely clear regarding these disasters on my main website.

As to the people who buy them, it has to be as a result of their existing inefficient filter systems, sales patter given by the seller or the labour-free convenience of sitting them on a patio and starting them up immediately – or probably a combination of the three.

To explain once more what happens with these ‘Plug and Play’ boxes is this: –

That’s the theory anyway but that’s a million miles away from what really happens as many, who have smashed these items of magnificence up in desperation after finally realising how useless they are, will bear witness.

This shows just one example of the many units available, yes they do trap debris, they have to do but for how long they do this is another matter. As to how efficiently they get rid of this putrid collection that is building up constantly is also pure wishful thinking.

It also does not take a man of science to realise that this would be far more easily achieved by way of a very, very long tube with the same diameter bore of the pump outlet stuffed full of discarded ladies’ tights. But how to clean the tights periodically in order to remove the debris is another matter altogether!

The good news, for the numerous manufacturers, is that no one can actually SEE the time bomb that is ticking away within!

These units readily-available today are all derivatives of the original swimming pool sand filters used for many years and are still successfully used today for this purpose PURELY AS ‘MECHANICAL STRAINERS’. They do their excellent trapping and discharging work aided tremendously by chlorine bleach-based additives in the swimming pool water but please do not try this with fish!

Over the years many budding would-be ‘Koi entrepreneurs’ have picked up on these units whilst taking a swim and thought that this may be ‘a good earner’ if made to look revolutionary and very technical in appearance. The sad part is these people actually believe their ‘inventions’ work but I’ll bet not a single one of them even keeps fish – let alone Koi!