(Published in the Spring 2007 Issue)
Overflowing With Options
The Ins and Outs of Filtration and Pumps
By Scott and Ann Springer
The market currently overflows with different types of filtration and pumps available to koi pond hobbyists. Having so many options—with many of them increasingly more high-tech—may confuse you as you search for the type of filtration and pump systems that will work best for you in your koi pond.
“Water quality is everything,” says Timothy Gilbert, the past president of the Rocky Mountain Koi Club in Colorado. “Spend the money on a nice filter system, buy more than you need, and you’ll have a nice pond.”
For example, if you are building a 5,000-gallon rectangular pond, Gilbert recommends buying a filtration system that can handle no less than 10,000 gallons.
“People always want just one more fish,” Gilbert says. “Generally speaking, people always have a greater fish load than they ever anticipated having.”
Gilbert knows about growing pains from personal experience. He built his first pond, a 700-gallon pond with no bottom drain and no skimmer, in 1998. After “catching the bug,” and learning from his mistakes, he built a 12,000-gallon pond a year later.
Consider all of the options on the market before you settle in which types of filters and pumps you will invest. “Make your filtration system as easy as possible to use, because the easier it is to use, the better your water quality will be,” Gilbert says.
Bead and Sand Filtration
While his smaller pond may require more manual labor, Gilbert revels in the ease of use of his pressurized bubble bead filtration system in his larger pond.
“I don’t have to wash things by hand; I just turn the valve and the pond basically cleans itself,” Gilbert says.
The initial cost of bead filtration typically ranges from $500 to $700 for an average-sized pond. The daily maintenance on the filtration may be little or nothing. Some types of bead filters are self-cleaning and will automatically flush themselves.
These pumps also have a life expectancy of about 10 years if the user does a weekly flush that takes less than 10 minutes to complete.
Occasionally, the beads will “channel” or stick together, Gilbert says. “I open up my filter and stir the beads around about once a month so it will work properly.”
Thousands of plastic beads, which are housed inside the filter, trap debris in the bottom chamber, while the clean water rises to the top and is released back into the pond.
Sand filtration works in a similar fashion, trapping debris in between a series of tubes that hang between the sand and the clean water passes through the tubes and returns back to the pond.
This type of filtration is rather economical and runs anywhere from $300 to $600, but may require quite a bit more upkeep than other systems.
“The algae accumulates in it and it may require a lot of maintenance and work because you will have to backwash every day or every other day,” says Timothy Czech, KHA, the president of the Pioneer Valley Water Garden and Koi Club in Massachusetts. “Most times people that start out with sand filtration end up buying a bead filtration system down the road.”
Both bead and sand filtration require a certain degree of skill to install. “You will need to know the basics of plumbing, or have someone who knows the basics of plumbing, help you install it,” Czech says.
Biological and Mechanical Filtration
Mechanical filtration uses brushes or other devices to screen or strain the water to let large particles accumulate and fall out, says Todo Todorsky, the treasurer and past president of the North Florida Koi Club. “A mechanical filter gives you physically but not chemically clean water because of the ammonia from the koi.”
Biological filtration works as the second step to mechanical filtration by making the water chemically clean.
Biological filters have a large surface area on them for two types of “good” bacteria to grow. The first set of aerobic bacteria eats the ammonia and converts it to nitrites, then another set of bacteria coverts the nitrites to nitrates, which are returned to the pond water and used as pond plant fertilizer. This is commonly known as the nitrogen cycle.
These types of mechanical filters vary in style, design, and complexity, so costs and installation requirements are also variable. “Most people could design a mechanical filter for as low as $100, but you could pay up to $500, depending on what you want to do,” Czech says.
Czech uses brushes inside his Vortex filter to accompany his bead filter. “It enables me an added layer of filtration for anything that might get past my bead filter,” Czech says.
A Vortex may be rather labor-intensive to install, Czech warns, but if well maintained it can last many years.
Biological filters also vary in price, depending on the type of filter you purchase. “The cost depends on how sophisticated you want to go,” Czech says. “You can buy one for $100, but if you buy one with a UV unit in can run up to $700.”
UV Units—Integrated and External
“I’ve done it with and without UV lights and I’m a believer in UV,” Czech says. “Before I had the UV light, my pond looked like pea soup.”
Some enthusiasts preach that you don’t need a UV filter, but Gilbert believes these filters offer multiple benefits and should not be left off a wish list. “It keeps my fish happy and healthy because it keeps my bacteria level lower,” Gilbert says. “It disrupts the cell wall of anything that goes through there.”
While the abundance of algae poses no direct threat to the health of the fish, it’s a major eyesore, and makes it difficult to check on the general health of the fish.
When using a UV unit as a filter, the water passes through the tube, the UV radiation kills the green algae, filters out the dead algae, and returns the clean water to the pond.
When buying a UV unit, consider the flow rate of the unit and the size of your pond. If your flow rate is too fast, the unit may not kill enough of the algae, Czech warns.
“The UV unit is a piece of cake to install as long as you can work PVC pipe,” Todorsky says.
The initial cost for a 40-watt UV light is about $300, Czech estimates. The bulbs, which cost about $40, should be replaced yearly. If UV filters are well cared for they can last up to a decade or longer.
Some mechanical filters or skimmers have UV units integrated into the filter already, but they can also be sold separately. Also, be aware that multi-purpose filters are attractive, but they pose problems when one element breaks down. If one part of the filter doesn’t work you may have to replace the entire system.
Skimmers
Skimmers are used as a pre-filter to catch things on top of the water before they go into the system and potentially clog another filter or a pump, Czech says. “I highly recommend people use skimmers,” Czech says.
Because skimmers are “the first line of defense,” according to Pamela Francis, a member of the Michigan Koi & Pond Club SE Chapter, they must be cleaned out frequently. Especially in fall and winter months in certain parts of the country, you may have to clean them out daily, Francis says.
While skimmers are effective, they must be used in conjunction with other types of filtration, Todorsky says. “The skimmer does exactly what it says it will do—take things off the top of the surface of the water—but it does nothing to clean the debris out of the bottom of the pond,” Todorsky says.
Owners of small ponds who buy from a kit may sometimes be under the illusion that a skimmer is all they need to filter their koi pond. “A skimmer doesn’t replace a proper filter system,” Todorsky warns.
You should also know that skimmers may be difficult to install after a pond is already established.
Mike Paddy knows this fact all too well. “The only thing I would add to my pond is one or two skimmers” in order to increase the margin for error, says Paddy, the president of the Michigan Koi & Pond Club SE Chapter. But Paddy’s pond is already established and he’s not willing to jeopardize his pond to include these additional features.
Instead of using a skimmer, Paddy uses a leaf net in the fall to trap leaves on the surface and then he manually removes the debris that a skimmer would normally catch. A skimmer would be handy in the spring to help combat algae growth too, Paddy notes.
“If you try to install a skimmer in an existing pond, you’ll have to cut the liner, which can be nerve-wracking to think that you could ruin your liner,” Czech says. “It’s also harder to ensure a good seal on a liner that is dirty.”
If a skimmer isn’t installed properly, you could have constant water seepage from the area where the skimmer was installed. “Anyone with a handy man’s ability could put one in, but if you’re all thumbs you could run into some problems,” Todorsky says.
Pumps: The Pulse of the Pond
A pump may serve as the heart and soul of pond and it can greatly affect water quality. You should consider several factors before you purchase a pump for your pond.
“You need to look at the flow rate, the head height, what the maximum head height is, the power draw, the life expectancy, and the warranty of the pump before you purchase it,” Gilbert says.
You also need to know exactly how many gallons your pond holds. “You’d be surprised to find out how many people really don’t know how many gallons their ponds hold,” Gilbert says.
He recommends reading your water meter before filling your pond to determine your pond’s capacity.
External v. Submersible Pumps
External pumps tend to be favored over submersible pumps by many koi keepers for several reasons.
First of all, external pumps tend to be more energy-efficient, especially magnetic-drive pumps that may use the same wattage as a light bulb.
“Submersible pumps tend to be more energy consuming than an external pump, which recently have become more energy-efficient in recent years,” Czech says.
However, some submersible pumps, particularly magnetic-drive pumps, can still be rather economical.
Paddy has used a submersible magnetic-drive pump on his 5,500-gallon pond since 1996, and he says the energy savings are immense. “I’m sure I could upgrade and get a newer mag-drive pump, but so far I have no complaints about my electrical bills,” Paddy says.
The submersible pump pureed the debris on the bottom of Paddy’s pond, so Paddy installed a settlement chamber filter system to combat the pollution. “I only have to maintain my filters once a year since I put the settlement chamber in,” Paddy says.
Safety may also be a concern. While submersible pumps are intended to safely mix water and electricity, an unintended accident may occur, such as a rock cracking a pump, Czech says.
“There is also a risk of having electricity in your pond if the submersible pump shorts out or has some other problem,” Czech says.
External pumps are easy to maintain and service because you don’t have to get into the pond to retrieve them.
Submersible pumps must be removed for cleaning. “I am constantly monitoring my water flow in my smaller pond,” Gilbert says regarding his submersible direct-drive pump. “I have to manually back-flush it.”
In summer months, Gilbert cleans the pump twice a week. He uses his small pond as a quarantine area and keeps his water immaculate to help boost the immune system of these fish.
In addition to being difficult to access in a deep pond, the removal of the pump may disturb toxins at the bottom of the pond which may make your fish ill.
While external pumps may have some definite advantages, they are quite bulky and hard to disguise. “If you have the space, and can hide them the external systems work well and can handle very large volumes of water,” Francis says.
Scott and Ann Springer are freelance writers living in Southern California.
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