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Simple steps quickly rehabilitate your old or inherited pond.

by Mike Garcia

reviving your pond

Ponds wind up in distress when left neglected over a period of time. Owner illness, extensive travel or home sales cause the most neglect; at other times, new home buyers find that they now own a pond but have no idea how to keep it in shape. End the neglect with a quick and easy rehabilitation treatment.

Pond rehab depends upon several factors. The largest comes from knowing what material composes the pond, typically concrete or liner. Identify this material and start your work.

New Life To Old Liners

If your pond floor consists of rocks and gravel, you likely have an EPDM-lined pond. These suffer from neglect in two major ways: leaks and equipment failure.

Lessening Leaks

A half-full pond means that a leak might exist at the lowest point. Determine this before restoring your pond. If you find that you have a liner pond filled with gravel at the bottom, proceed with a pond clean-out. This will jump-start your existing liner pond.

First, remove all existing fish and plant materials from your pond. This mimics what Mother Nature does every year to ponds that freeze.

The best time for a pond clean-out is early spring, before the weather becomes warm. If you clean out during the warmer months, you might get algae bloom. The bacteria that starves out the algae will need time to re-colonize.

Catch your fish, frogs and water turtles with a fish net, and place them in a large plastic tub filled with water from your pond. Cover the tub’s top with plywood or another material; stressed fish might jump out of the tub. Nothing is more heartbreaking than to return from a lunch break and see a large dead koi next to your pond.

Dress for the occasion by putting on a long pair of rubber boots (waders). Rubber gloves help if you are not used to handling "fish muck." Arm yourself with cutting shears for cutting back overgrown water plants and lilies.

Next, drain the pond. If there is no bottom drain, use a submersible pump with a long discharge pipe. Place the pump into the pond, allow it to suck up the water, and discharge it into your garden.

Pond water makes for some of the best plant fertilizer in the world, so don't waste it. Douse your entire garden in this pure form of organic nitrogen.

Clean Scene

Once you drain the pond, hose it down with a high-pressure nozzle attachment. Wash the pond algae and scum off the rocks and boulders.

Do not attempt to clean off every square inch of algae; leave some on the rocks. This will help your new pond establish itself more quickly by allowing beneficial bacteria to colonize quickly. Spray the highest rocks and boulders first, and work your way down toward the bottom of the pond. Then pump out the resulting water.

Have a mechanical skimmer filtration box? Clean it out, too. Remove all the water and the submersible pump. Hose down any filter mats, nets and debris-catching brushes.

Next, empty the biological waterfall box. Remove any filter media, such as filter silk, lava rock or whatever it utilizes to colonize beneficial bacteria.

This task takes time. Depending on the size of your pond, you might need the entire day to complete it (provided you have experience). For assistance, hire a professional for best results.

Now check the liner for potential leaks. Carefully inspect for low points; with time, all soil will settle in low spots. These liner depressions provide a point of escape for most of your water.

Look for areas outside of the liner that appear moist. Pack a small amount of sand underneath the liner to build up the low points.

Sometimes, a nearby tree sends out roots that penetrate the liner and create massive holes, resulting in the need to replace this part of the liner - or the entire liner. Queen palm trees in particular pose problems if planted too close to the liner.

Turn on your pond lighting system, and replace burned-out bulbs. At this point, you can add more lighting.

After cleaning out the pond, begin filling it. This pond clean-out procedure safely ensures that your system will re­establish its biological ecosystem. Jump-start your ecosystem by adding generous amounts of dechlorinator and beneficial starter bacteria as you fill the pond with water.

Is there a magic pill when it comes to beneficial bacteria? Not yet, but some Nitrosomonas and Nitrobacter bacteria seems to be the next best thing.

Concrete Evidence

If you find yourself the new owner of an existing concrete pond, you probably have what I call a koi kichi pond. A few simple principles of these pond systems can undergo simple renovation that will result in a stunning backyard jewel.

Pump Primer

Koi kichi ponds differ from traditional water gardens in that they are deeper (approximately 4 feet deep) and include an external pump, pressurized bead filters, bottom drains, a skimmer and an ultraviolet sterilization light.

If the pond does not flow, check the external pump first. External pumps usually hardwire into the house electricity system.

If you turn on the pump and nothing happens, then call your local pond professional to switch out the pump, or take a look at the pump brand and model number. Write down these names, and plug them into an Internet search engine. If you can't make it to a store to purchase a replacement, you might order pumps online.

Once the pump arrives, call a licensed electrician to remove the old pump and install the new pump. After the new pump is running, check out other components for this type of pond system.

UV lights used for water quality provide a major component of koi kichi ponds. A UV light zaps algae with intensive amounts of ultraviolet rays, killing the algae en masse.

The most common problem with a UV light is the actual light bulb. These generally last for only months and should be checked and changed regularly. This usually makes for a very simple operation, not much harder than changing a light bulb in your house.

Leak Liabilities

What happens if you drain and refill the pond, only to come back an hour later and find it's lost tons of water? You have a serious leakage problem. The most likely leak sources come from the concrete shell or bottom drain.

The first step to determine where a leak originates is to turn off the pump and let the water leak to the lowest point. Once some time has passed, the final water level will show you the leaky spot.

If the water drains only at the top, the leak is in the top area. If the entire pond leaks until it completely empties, the leak sits at the bottom of the pond. This could signal a faulty drain or a break in the concrete shell. Over time, hairline cracks can form in mortar or grout joints as well as concrete.

Concrete shell cracks used to mean big trouble. The concrete had to be removed with a jack hammer and repoured. With the advent of new chemical compounds, a new substance called polyurea remedied many of these situations.

You might know polyurea from some of its modern-day applications, such as nonskid surfaces. Polyurea applications once were very expensive, because the trucks and rigs used to spray polyurea run upwards of tens of thousands of dollars.

Recent innovative application methods have created a price drop. You now can purchase polyurea at a reasonable cost. When properly mixed, this homeowner-friendly product will seal any concrete pond leaks in a matter of minutes with long-lasting results.

If you've checked for low points and completely resealed the entire bottom of the pond and it still leaks, then check for faulty waterlines. Poorly made flex tubing can develop tiny pinholes, which develop into bigger holes over time. Also, if you or your pond installer let excess pipe glue from PVC pipe installation remain, the solvent inside the glue might corrode the exposed pipe and result in leakage.

Filter Failings

An old bead filter presents a challenge to renew if left dormant. If so, prime the pump, and turn on the system. Now attempt to back-flush the bead filter. If this works, then you're in business. If the back-wash part of the bead filter does not work, contact the manufacturer to report it.

With the explosion of many new bead filters on the market, the process of running your inherited bead filter might differ from your experience. Some bead filters have a life time warranty on parts or the whole product.

Bead filters require just a few items to function at their optimum: a temperature of about 60 degrees Fahrenheit or higher; ammonia or nitrites; a stable pH of 7.0 to 8.5; and hardness levels over 80 ppm (parts per million) with respect to calcium carbonate. Optimum levels should be 125 to 150 ppm.

A New Deed – A Pond in Need

When you inherit an older pond, don’t make a mountain out of a molehill. You can find many great resources through local retailers, clubs and websites to help get your pond back into top shape.

Mike Garcia is the founder of Enviroscape Inc. and serves on the board of directors for the International Landscape Alliance (