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All BEAD FILTERS Are NOT Created Equal
a Product Comparison by the Pond Doc
Years ago I wrote an article entitled All Filters Are NOT Created Equal (which, by the way, I really need to update!). It delves into the different types of filters on the market, explaining what they are, how they work and the pros and cons of each type. Since that article was written the bead filter has grown so much in popularity with its hands-off backwashing capabilities that it's spawned a whole array of pressurized, back-washable filters. Some of them are not bead filters at all but look exactly the same on the outside.
These masqueraders (such as Aqua UV's Ultima II and comparable filters) claim to provide both mechanical and biological filtering. They are less expensive than the true bead filters such as the ProBead and Aquadyne. People who have bought them with whom I've spoken often thought that they were getting the same quality for less money and did not realize that they were getting lesser filtering capabilities. Perhaps this article can help people know exactly what they are buying.
For the sake of this article I will call the true bead filters "bead filters" and I'll call the other "tube filters" because that's the type media they use.
So what exactly is all the fuss about? What is the difference between a bead filter and a tube filter?
The biggest difference is in the size and style of media used. In true bead filters a small, floating plastic bead is used - usually around 1/8 to 1/4 of an inch long. Thus we get the name "bead filter". The smaller beads capture fine particles resulting in a more thorough mechanical filtering of the water. In the tube filter long, plastic sinking tubes are used. These are not beads at all and are much larger than the beads used in bead filters. They allow smaller particles to pass right through and do not filter as fine.
The problem with using beads has always been that the beads clump and must be broken apart. They clump because they are doing their job of mechanically removing the finer particles from the water -- it's the nature of the beast. Backwashing with a high-pressure flow of water must be used to break these clumps up and release the particles so that they can be washed away through the waste port. Often a 2-speed pump is used in conjunction with a bead filter. If the pump is sized properly, the low speed of the pump runs when filtering so that the water isn't flowing so quickly through the filter that it's unable to trap the particles. The high speed is used during backwash to break up the beads. Another method of breaking up the beads and releasing the particles so that they can be channeled to waste is by attaching a blower to the bead filter. The blower is run first before backwashing. Air at high pressure is blown into the unit to break up the beads. A blower on a bead filter will negate the need for a 2-speed pump and is often preferred.
The manufacturers of the tube filters will claim that a blower or 2-speed pump is not needed with their filter. They are correct. The tubes, by design, do NOT trap the smaller particles therefore the clumping isn't as much of a problem. If the tubes do not filter out the trash there's nothing to clump up. If there are no clumps of course you don't need the blower or 2-speed pump. What it all comes down to is a filter that does not need to be cleaned is not filtering anything. There is a positive to the tubes. They are good biological media. If one has no need for mechanical filtering the tube filter is probably a good choice. A reason one might prefer a tube filter is if it's intended for water gardens where fine filtration is not desired.
The ProBead™ uses a mixture of three different sizes of floating beads. It has the tiny beads famous for providing fine mechanical filtration, a medium-sized bead for mid-level debris and a larger floating media for housing nitrifying bacteria. This is an improvement on the classic bead filter because it increases its biological filtering capabilities tremendously while leaving its mechanical filtering capabilities in place.
Another difference in the bead filter and the tube filter is the way the water flows inside the body of the filter. In the tube filter the water washes down from the top of the 6-way valve through the tube media and is pulled out through the laterals. It's exactly opposite on the bead filter. In fact, this is why the tube filter is cheaper. There is not as much cost in the manufacturing end. It takes a lot more time and materials to properly plumb a bead filter.
The bottom line is that bead filters still reign supreme when it comes to combining the best of mechanical filtration with biological filtration while maintaining hands-free and low-maintenance operation. Although the tube filter never claims to be a bead filter the lines are blurred. If a bead filter is the level of quality you are seeking for your pond you are now armed with a little more knowledge so that you know what level that filter is at!
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