ith the popularity of backyard ponds growing, so have the chances of pool and spa professionals being asked to service them.
“The number of ponds that I see is at least doubling every year,” says Michael Breen, owner of Breen Acres Aquatics, a full-service pond maintenance and stocking company in Loxahatchee, Fla., which breeds and ships fish around the country.
The pond business is expected to continue to grow, say industry experts. That means a new and lucrative service to add to your business. Breen charges a flat rate of $75 per service call, which includes chemical water analysis, scrubbing algae, trimming aquatic and terrestrial plants, and a filter cleaning.
For weekly visits to commercial accounts, he charges approximately $550 a month.
If the pond needs a change of water and complete cleaning, he will charge $1 per gallon for small ponds (up to 350 gallons) or by the hour ($45 to $75), depending on the pond’s size and condition.
As a pool service technician entering the pond business, it’s important to know how to maintain biological ponds. These installations can feature plants, fish and other living entities. Abiological ponds, which are sometimes called “poison systems,” contain no fish or plants.
This article focuses on biological installations, which require a different approach than traditional pool and spa care. The following tips and techniques will help you get started and, it is hoped, add to your company’s profits.
Filter facts
The two primary methods of pond filtration are mechanical and biological. Mechanical filters remove solids from the water by trapping debris in a mat, brush or sponge. These filters work well, but require frequent cleaning.
The biological filter is the most effective method of removing toxins from pond water. With bacteria as the active component, it breaks down ammonia into nitrite and then into nitrate. In a biological filter, the bacteria are placed on material where they are exposed to large quantities of food and oxygen. Often this is a fiber matting medium, which offers a large surface area for bacteria to colonize.
“One of the big things in the koi pond industry right now is something called the poly bead filter,” Breen says. “It looks like a sand filter, but the flow comes in from the bottom. It causes turbulence, making the beads go up and down. It’s on these beads that you can grow a colony of bacteria.”
Biological filters in ponds must run continuously. If they are shut down for more than a few hours, the beneficial bacteria will begin to die. Bacteria for such media are available at most garden centers.
“I start with dry bacteria that you can find at most pet stores,” says Phyllis Zeigler, owner of Pond Pro in Shawnee Mission, Kan. “You can put it in the filter or mix it with water in a 5-gallon bucket and then add it to the pond.”
A biological filter should be cleaned with dechlorinated water to avoid removing or killing the beneficial bacteria. Also, the filter should not be overcleaned. Rinse the media only enough to allow good water flow through the filter.
If the pond in question has a mechanical filter, check the pads regularly and clean or replace as needed. If the pads become clogged, it can slow down the flow of the circulation system, destroying the effect of any waterfeature on the pond and inviting algae growth.
On a related note, if you’re performing a filter cleaning, this is a good time to take a look at the pump, too. Cleaning the pump’s impeller regularly (every two to three months) keeps it working at peak efficiency.
A bloomin’ problem
Eventually, any biological pond system will develop algae. Most likely, it will appear in the springtime. As nutrients increase, the sun grows warm and bright enough to encourage new growth.
Not to worry. Most of the green water will disappear as the other plants mature, consuming the nutrients and growing tall enough to block sunshine from the water. Remember, green water is not harmful to plants or fish; it’s just not aesthetically pleasing.
If green water is unacceptable to you and/or your customer, there are options. Once the filter is conditioned with bacteria, it probably will keep the water clear. However, the pond is always vulnerable to any organic debris such as phosphates, which can blow in and cause an algae outbreak.
“There must be a kazillion ways to combat algae, but not everything works in every pond,” Zeigler says. “When something does work, we write it down: any combination of chemicals or conditions and how it is to be used.”
If you’re going to use an algaecide, be sure it’s made especially for ponds and aquatic gardens. It should be approved by the Food and Drug Administration for such use. Here are two ways to control algae in ponds:
Flocculants: Flocculants can be sprayed across a pond’s surface, where the chemical will form a cloudlike layer on top of the water. The layer slowly sinks, catching any suspended material, including the algae, as it drops. The pump should be off during this process. The resulting layer of sludge then can be removed from the pond bottom by siphoning or filtering.
UV clarifiers: UV clarifiers work in conjunction with the filter and can be easily plumbed into the circulation system. Sometimes called an ultraviolet sterilizer, the device uses a small germicidal UV lamp that is placed in a pipe to allow water to pass around it. It will cause nearly 99 percent reduction in algae when properly sized to the pond.
However, a UV sterilizer cannot be used without adequate biological filtration because the dead algae still will need to be broken down further. The process can remove oxygen from the water, so you have to be careful to keep up the aeration, creating lots of water movement.
You may eventually discover a more insidious form of algae in the pond. Filamentous algae resembles clumps of stringy green horse hair and is more damaging because it can block the sun, wrap itself around plants, such as waterlilies, and form cloudy masses on the side of the pond.
Algaecides don’t work as well on this strain, so hand removal may be necessary. To do this, use a length of PVC pipe and cut the end into strips so it resembles a forklike device. Place the roughened end into the pond and twirl the other end between your hands. The algae will wind onto the pipe like spaghetti onto a fork. Another option that works in the same fashion is a toilet brush.
While there are many ways to combat algae, Breen says it’s best to maintain the pond water in a way that will make it inhospitable to the bothersome plant. “We look for things that are out of balance,” he explains. “Is the bacteria level too low? We use a product that is based on what the bacteria would be in a pond in early spring or fall. We double the dose for the first two [applications] and then bring it back down to the required amount.
“You can’t put in too much bacteria. It’s like taking an aspirin for a headache. You try it first and see if it works.”
The water itself
Water chemistry is important to biological pond systems, but not the same way it is for swimming pools. For example, ponds with living creatures don’t use chlorine or stabilizers. Here’s a look at some key water chemistry variables and how they play a role in pond maintenance:
• Temperature
Being cold-blooded, a pond’s inhabitants can endure a wide range of temperatures — most experts say anywhere between 33 degrees and 80 degrees. In the winter, leave the pond’s surface frozen over, or keep it continuously free of ice so the water remains thermally homogeneous. It is not a good idea, however, to try to pound through the ice with a hammer or other tool. Fish can hear and the stress could make them sick.
• pH
Water containing fish should be kept within a pH range of 6.5 to 7.5, with 7 (neutral) being ideal. Use the same pH test kit you would with a swimming pool. The key with biological ponds is to avoid large pH fluctuations. Unless the pH is below 6.5 or above 8, it’s best not to try to adjust it. If you do need to adjust it, pH-up and pH-down formulas for biological ponds are available.
• The nitrogen cycle
The nitrogen cycle may seem like a complicated scientific riddle. But basically, it’s the sum total of the processes that convert nitrogen into compounds that are useful to animals and eventually cycle their way back to their original state. The compounds include ammonia, nitrite and nitrate. Ideal ranges are:
— Ammonia: < 0.25
— Nitrite (NO22-): < 0.1
— Nitrate (NO3-): < 50 ppm
Test kits are available that measure these numbers for you. While awareness of these measurements is not a prerequisite for success, conscientious technicians will want to track what is happening in the systems they service.
Note that heavy concentrations of these elements can be deadly to living creatures. If the readings for ammonia, nitrite and nitrate soar too high, you may need to change the pond’s water and begin again.
“I’m not a big fan of doing weekly tests,” Zeigler says. “The more you tinker with the water, the more complicated it becomes to keep the eco-balance going. [With ponds], you are always going to combat algae and cloudy water.
“But with man-made ponds, [these problems] often get taken care of by nature. If someone says the pH is low and they want to treat it for pH bounce, I think you’re asking for trouble. It should fix itself naturally.”
