Lies, Damned Lies and Pond Flters. Review of The Hozelock-Cyprio Saturn Quattro
Let Me Tell You the Truth About Pond Filters
It is still happening. Massive amounts of competition in the pond filter market and the battle for margin is resulting in pond keepers being bombarded with techno-speak in an effort to increase sales of highly priced pond filters.
The latest product I came across prompted me to write this particular article although I've written about the subject many times.
One of the most-read articles I've ever written is called "What really happens in a fish pond filter?". Here's a link to that article. Pond filters ... this is how they all work
You will find it useful to refer to this article to follow what I'm about to say more closely.
My chemical engineering background has helped me greatly in separating fact from fiction for many pond products. Here's one more of them.
The Hozelock-Cyprio Saturn Quattro
This is the name of the product I came across and about which I want to write since it prompted me once more to demystify pond filtration.
Up front let me say that I have no doubt that this filter will perform extremely well. However it is just another way to part a pond keeper from his/her money. For the vast majority of garden ponds it is overkill. And overkill by a long way.
Not only that; an enterprising DIYer could achieve a very similar water quality result at a fraction of the price. The RRP is I believe £549.99 for the 12,500 litre and £699.99 for the 20,000 litre model.
The REAL Reason Why This Filter Works Well
The reason has very little to do with any specific component. However it has much to do with the process cleverly implemented in this product.
Reproduce this process in any box and you will get similar results using any old bits of plastic.
Much is made of the design being built around the experience gained in Kaldnes systems.
The biomedium used is called Kaldnes K1 which is a very good plastic biomedia but in its simplest form Kaldnes 1 is a "fancy" round piece of plastic with a density slightly more than water. It's design arguably is different and better than similar cylindrical designs of mass transfer media in terms of surface area per unit volume. However this difference is slight as can be proven by simple calculation.
This means that Kaldnes if left to its own devices in a static volume of water the Kaldnes would sink just like any other plastic cylinder of the same density would.
The plastic surface is the substrate onto which bacteria cling. They will cling to any surface.
Now here's one of the 2 major secrets ...
If the mass of water holding the Kaldnes can be agitated then the Kaldnes will remain in suspension. Such a state of suspension is perfect for effective bio filtration of any kind.
The turbulent mixing of biomedia within a polluted body of water will allow bacteria and contaminants to come in very close proximity with each other continuously. This means bacteria can break down toxins (ammonia and nitrites) and have the resulting nitrate chemicals removed instantly. I call this "Flushing"
In other words ... old water is immediately replaced by fresh water due to agitation which makes space for the next bit of contaminant to come into contact with the purifying bacteria. This bacteria food is devoured by hungry bacteria.
If there was no agitation the bacteria would tend to starve to death or become sluggish waiting for the nitrate to be removed and new food, oxygen in fresh water, nitrite or ammonia to come along.
Without agitation the water at the boundary of the plastic interface is essentially static or dead.
How would you feel surrounded by stuffy impure saturated air while feeling very hungry and losing weight and nutrients fast? A bit under the weather for sure.
Just think of how a dish washer works or a washing machine. Leave the dinner plates in a static pool of water and they never come clean. Swish the water around and how easily the dirt is removed. This is a simple mechanical rather than a biological process however but it illustrates the principle of boundary layer dynamics well enough.
This is what you need to know ...
All Biofilters of any kind will perform better in an agitated state. Period.
And the Second Major Secret Is ...
Oxygen contained in circulating pond water.
Those millions and millions of purifying bacteria in any pond filter system need Oxygen, Food and a Flush to remove products of biological purification to do a good job. Just like we do ...
In a well agitated system even without extra aeration pond keepers will see major improvements in pond filter efficiency.
When you add extra air to keep water saturated with oxygen then the bacteria are at their most virulent. They mop up the impurities (ammonia and nitrites) in no time at all and the "Flush" from agitation allows them to start all over again with fresh oxygen, fresh food and clean water.
These are the keys to great pond filtration.
The Hozelock-Cyprio Saturn Quattro uses a venturi system to add oxygen and create agitation at the same time. You can do the same ... a venturi costs a couple of Dollars.
I compliment Hozelock in putting together a well manufactured biofilter. I hope however you now realise that somewhere in the marketing mix the principles are a little bit overstated.
At least you can now have a sensible debate with your reailer and make an advised judgement on the price asked.
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Series of 12 different Excel pond calculators ... easy to use and very useful:
Useful Links for Important Equipment
Large biofilters and UVC ... large biofilters
Smaller Biofilters and UVC ... smaller filters for smaller ponds
Pumps ... How to select the right pump every time
You'll see links on my web pages to UK and USA suppliers I trust and recommend.
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Water Gardening Introduction To Pond Keeping Part 1
Water Gardening Introduction To Pond Keeping Part 2
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