830-515-2002

A Pool and Water Garden

Creating a pool and water garden is a big undertaking, but the reward—a dramatic focal point for your yard and a habitat for fish and exotic plants—is substantial. Furthermore, once the pool is completed, upkeep is not any more strenuous than for a traditional flower bed.

NEW MATERIALS TO LINE THE POOL

Garden pools once were made either of one-piece rigid fiberglass or poured concrete. Nowadays the material of choice is polyvinyl chloride (PVC) plastic or a synthetic rubber called EPDM. With a life of a decade or more, these pliable membranes conform to any pool shape, from geometric to a free-form outline that is meant to mimic a natural pond.

Pool liners are available in a variety of thicknesses; 45 mils (a mil is inch) should be sufficient for a backyard pool. When you purchase the liner, it will come folded and boxed and is ready to set in the excavation.

CHOOSING THE PROPER SITE

Since the banks of the pool must be level all around, select a location on nearly flat terrain. To ensure sunlight for plants and fish, avoid placing the pool directly under a tree.

Some jurisdictions require a fence around pools, usually if they are more than 18 inches deep. Check your local building codes before you break ground.

FINISHING TOUCHES

To protect the liner from direct sunlight where it extends above the water line, trim the pool with a coping of flat, thin landscaping stones that overhang the edge. Unless you expect the pool area to receive heavy foot traffic, there is no need to set the stones in mortar.

A pump and fountain not only add a decorative touch to your pool but also will prevent insects from breeding on the pool’s surface by keeping the water in motion. Select a fountain head and length of plastic piping in order to create the spray effect that you desire on the surface of the pool.

To power the pump, tap an electrical circuit in the house and extend it to the pool with UF (underground feeder) cable of the same gauge as that of the house circuit. Protect against shock with an outlet containing a ground-fault circuit interrupter (GFCI). Alternatively, have an electrician run a new circuit protected by a GFCI in the service panel. Or choose a solar option to avoid running cords.

FLORA AND FAUNA

Before stocking a pool, treat the water with a liquid dechlorinating agent available from pool suppliers. Since plants in containers need shallow water, either dig the pool with a 9-inch shelf around the perimeter or stand the containers on concrete blocks.

TOOLS Tape measure Powdered chalk Shovel Wheelbarrow Edge cutter Spade Carpenter’s level Garden rake Scissors Push broom Electric drill MATERIALS Ropes or hoses Lengths of 2-by-4 Sand Pool liner Landscaping stones Dechlorinating agent 10-inch galvanized spikes UF electrical cable Conduit, nipple, elbow, and bushings LB fitting Metal strap Concrete block Outdoor outlet box GFCI receptacle

CAUTION

Before excavating, note the locations of underground obstacles—electric, water, and sewer lines, or dry wells, septic tanks, and cesspools.

Calculating liner dimensions

Use the length and width of your pool in feet with the formula above to determine the size liner required. Apply the formula twice, once to find liner length and again for the width. Ignore any shelf you have planned for the pool perimeter; it does not affect the results.

Length/Width of Pool 2 × Depth of Pool Length/Width of Liner
_____________ + _____________ + 4 = _____________ feet

EXCAVATING THE POOL

EXCAVATING THE POOL

Marking the dimensions

Outline the shape of your pool on the ground with a rope or hose. Then lay a second rope or hose 1 foot outside the first to mark the strip of sod to be removed for a stone coping. Measure across the pool outline at its longest and widest points (left), then use the formula above to calculate the size of the liner you need. Squeeze powdered chalk from a chalk bottle along both markers, then lift them away.

Preparing the hole

Starting at the center of the pool outline, excavate to the desired depth—plus 2 inches for a layer of sand on the bottom. For a shelf, leave a ledge 1 foot wide about 9 inches below ground level. At the pool perimeter, slope the sides of the hole and any shelf about 20 degrees. Cut along the sod line with an edge cutter (right), then remove the sod inside the line with a spade.

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Leveling the banks

Rest the ends of a 2-by-4 on opposite banks, inside the sod line. Level the board, if necessary, by removing soil from the higher bank. Mark the banks under the 2-by-4 with chalk. Leaving one end of the board on one of the marks, set the other end on the bank at a third point. Add or remove soil there to level the board, then mark that spot with chalk. Repeat this procedure to level several other points along the banks, always keeping one end of the 2-by-4 on a point that you have already leveled. Add or remove soil between these points to bring the entire bank to the same height.

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Checking the depth

For a level pool bottom, mark the desired depth on a scrap of wood to use as a guide. If the pool will have a shelf, add a second mark to the depth guide 9 inches below the first. Lay a 2-by-4 across the excavation and hold the depth guide vertically against the 2-by-4 (right), checking at several points for high and low spots. Use the 9-inch mark at the shelves. Add or remove soil to level the shelves and the bottom. Repeat at various points that span the hole.

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Preparing the bottom

Shovel sand into the hole to cushion the pool liner. With a garden rake, spread the sand across the bottom in an even layer 2 inches thick. Do not sand the shelf.

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LAYING OUT A PLASTIC OR RUBBER LINER

LAYING OUT A PLASTIC OR RUBBER LINER

Spreading the liner

Place the liner in the hole and begin unfolding it, working toward the banks. With a helper, contour the liner over shelves and up the sides (left). Avoid overlapping folds in the liner and make sure it covers the sod line. Temporarily anchor the liner with coping stones set at several places around the edge. Fill the pool with a garden hose. Shifting anchor stones as necessary, smooth the liner so that the rising water presses it flat against the sides. Add dechlorinating agent according to the manufacturer’s directions.

Securing the liner

When the pool is full, trim the liner along the sod line with a pair of scissors (above). To permanently anchor the liner use a hammer to drive 10-inch galvanized spikes into the banks 4 inches inside the sod line, every 2 feet around the perimeter.

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Laying the coping

Place the pump in the pool and run the power cord onto the bank where you plan to install the outlet. Spread 2 inches of damp sand between the sod line and the pool edge. Set the coping stones in the sand around the perimeter of the pool so that they extend at least 1 inch over the edge (above), protecting the liner from deterioration caused by sunlight. Sweep sand into the gaps between stones with the push broom.

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ELECTRICITY FOR A PUMP AND FOUNTAIN

ELECTRICITY FOR A PUMP AND FOUNTAIN

An exit from the house

Dig a trench from your house to the receptacle location. Make the trench 6 inches deep if you plan to install rigid metal conduit for the electrical cable; otherwise make it 12 inches deep. Widen the trench near the pool to fit a concrete block. Drill a ⅞-inch hole through the house siding and floor framing to accommodate a ½-inch-diameter nipple, a short length of threaded conduit. To the back of an LB fitting, a small box used to direct cable toward the trench, screw a nipple long enough to extend into the basement or crawlspace (above, left). To the other end of the LB fitting, fit a length of conduit that reaches at least 6 inches into the trench. Screw a plastic bushing to the bottom of the conduit. Push the nipple through the hole into the house and secure the conduit to the foundation with a metal strap. Inside the house, screw a bushing onto the nipple.

Making connections.

Remove the cover plate and gasket of the LB fitting. Thread UF cable up the conduit and into the LB fitting, then push it through the nipple (above, right). At a convenient location inside the house, install a box for a single-pole switch. Run the UF cable to the box, then continue the circuit with indoor (NM) cable, preferably to an existing receptacle. At the switch, connect black wires to the switch terminals, white wires to each other, and ground wires to the switch and box (if it is metal) by means of jumper wires and wire caps. Replace the LB fitting’s gasket and cover plate, and caulk the joint between fitting and house.

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Installing the outlet box

Run cable to the end of the trench. Screw a bushing to one end of a 12-inch nipple; onto the other, thread an elbow connector. Then cut an 18-inch length of conduit; connect the threaded end to the elbow and the other end to a fitting called a threadless connector (inset). Thread the cable through this assembly, set it in the trench, and lower a concrete block over it. Slip a weatherproof outlet box over the cable end and screw it to the threadless connector (right). Pack soil mixed with stones around the conduit within the concrete block to prevent wobbling, then fill the trench.

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Connecting a GFCI receptacle

Cover both GFCI leads marked load with wire caps. Connect the black and white wires in the cable to the GFCI wires of corresponding colors marked line (left). Attach a jumper wire to the ground screw in the box and join the jumper to cable and GFCI ground wires. Fold all the wires into the box, screw the outlet in place, and attach a weatherproof GFCI cover. In the house, turn off power to the receptacle where you intend to tap a circuit. Connect the wires in the new cable to those in the box there, black to black, white to white, and ground to ground. After screwing the receptacle to the box, restore power, and then plug in the pump.

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MAINTAINING A HEALTHY POOL

MAINTAINING A HEALTHY POOL

Fish and plants work together to keep your pool clean and attractive. Aquatic plants provide oxygen and food for the fish, which in turn help keep the water clear by feeding on algae.

PERIODIC CLEANING

Drain your pool and scrub the liner every 3 to 4 years, or after an inch of silt has built up on the bottom. To empty the pool, lift out the plant containers, replace the fountain attachment on the pump with a hose leading outside the pool, then turn on the pump.

When about 6 inches of water remain, remove the fish with a net and place them in a clean plastic container (a new trash can works nicely) with water from the pool. Finish draining the pool, then disconnect the hose and put the pump in the fish container. Run the pump; doing so provides oxygen for the fish. Place the fish and plants in a shaded area.

Gently scrub the liner with a nylon-bristle broom, then use a wet-or-dry vacuum to suck the silt from the pool. Refill the pool and dechlorinate the water. When the pool temperature rises to within 5° of the water temperature in the container, net the fish into the pool and return plants to the shelf.

WINTERIZING A POOL

When the pool’s water temperature drops to 45° F., trim plants to a height of 3 inches and move them from the shelf to the bottom of the pool.

Fish can survive the winter without food, but not without oxygen that enters the water through the surface. In regions with mild winters, water circulation from the pump may prevent the pool from freezing. Should the surface freeze over, however, you must cut in the ice an opening of at least 1 square foot. In extremely cold areas, an electric pond deicer can keep a corner of a pool ice free.