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Instant Pond

Installing a pre-formed pond with waterfall filtration can be easy – if you follow the steps.

by Freddie Combas

preformed pond kit
Image source: Pintrest

When people want to start water gardening, they usually turn to easy-to-install, widely available pre-formed ponds. Although pre-formed ponds install fairly easy, they could present somewhat of a challenge to keep filtered properly depending on where you live. The hotter the climate, the harder pre-formed ponds are to filter. All “bad things” within a pond’s ecosystem thrive in warmer water, and dissolved oxygen is scarce.

The filtration systems specifically designed for this type of pond often are inefficient due to their true filtration capabilities (not what it says on the box) or too big in physical size and take up too much space inside an already small pond. This type of pond is very difficult to keep filtered properly for healthy water quality, clarity and an aesthetically pleasing overall project.

To help with most of the problems with filtering pre-formed ponds, look to other types of biological filtration systems. Here, you’ll find how you can install a pre-formed pond unit with a small biological waterfall filtration unit and a mechanical skimmer.

You can disguise the biological waterfall filtration unit within the new waterfall. It will look great aesthetically and deliver better filtration and aeration to the pond. Mechanical skimmer design for pre-formed ponds has come a long way in the last year. New skimmer designs allow you to better collect leaves and surface debris by offering larger “baskets.”

By adding these two filtration devices, you will create a healthier ecosystem within the pond and reduce the time and cost of maintenance throughout the year. Looks nicer and involves less work – what could be better?

STEP 1 Questions to Ponder

Once you've decided to install a pre-formed pond, choose the location where it will be placed. This sounds simple enough. In most of the cases that I get called to renovate or enlarge an existing pre-formed pond, however, my services are needed because of improper or impractical original placement.

When deciding the location for your new pond, ask yourself the following questions. You will avoid the "I wish I had ... " that commonly follows an improper placement of a water feature.

Where do you spend your time at home? Most people have an area in the yard that is bare and, at first impression, seems to be the right place for the pond. These areas usually are located in a far or out-of-the-way corner of the yard. Installing the pond in one of these areas would make it a “destination location” and would be enjoyed only by “travelling” to it.

What happens when it's too hot, it's too cold, it's raining, there are too many bugs flying around or you're entertaining friends? Always look for a location that you can view best from the most angles inside the home, especially wherever you spend most of your time, whether it is in the kitchen, on the couch or in your favorite recliner. Knowing this will allow for maximum enjoyment of the water feature, because you won't have to go out of your way to see and hear it.

Can you afford a bigger pond? Numerous publications over the years have claimed that the No. 1 mistake that beginning water gardeners make is building your first water feature too small. Unfortunately, I have found this to be a fact and not just a salesman's pitch to sell you a larger pond.

After listening to their wants and needs, I have had customers go against my recommendations only to later rip out the pond and enlarge the same feature. One customer requested that I redo and enlarge the pond and waterfalls while also adding a stream within two weeks of the completion of the original install. I installed the exact same pond recommended during my initial design consultation, which at the time they felt was "too big." Learn from others' mistakes; water gardening is a very addictive hobby.

Can you comfortably accommodate all the pond "extras?" Just as those special knick-knacks in your house make it a home, all those little "extras" will make your pond the little paradise getaway that you seek. Take into consideration the extra space that you might need for the landscaping, natural stone walkway, statuary, gazebo and fire pit.

Once the pond is built, you will want to landscape it, so you must know what type of landscaping (tropical, Oriental, English garden, etc.) you will plant to ensure that you leave the required room for the plant material. You might want a sitting area for a cozy bistro table for two, a bench or a place for an outdoor model train track. Consider the accent that will make it your personal place to relax in and enjoy.

STEP 2 Level Playing Field

Once you decide on the size of the pre-formed pond and where to place it, it's time to prepare the area. Before you dig, make sure that the ground is level. If you install the pond on a sloped area, the pond will seem to be full of water on one side while slightly empty on the other.

Imagine filling a cup of water almost to the top and tilting it one way. The water on one side reaches the cup's edge, and the water on the other side drop down and away, making that side less full. This visual effect will occur if you do not make sure that the pond area is level.

Leveling the pond can be done accurately and easily by using a laser transit or a line-level. Laser transits are used best in larger projects; since most pre-formed ponds are fairly small, we'll use a line-level for this example.

Lay the pond upside down on the area where it will be installed, spray-paint its maximum dimensions, and form a square. Insert a screwdriver into the ground, then tie a long piece of string to the screwdriver near the ground. Pick various points at the pond's perimeter, pull the string taut, and hang the line-level at the chosen point.

Now move the string up or down until the bubble aligns between the two lines at the center of the line-level. If, when the bubble is between the lines, you are above groundlevel, the end with the screwdriver is lower than the side with the level. If the opposite occurs, the line-level is higher than the screw­driver side, and you must remove the screwdriver and place it where the line-level measurement was taken.

Doing this will make it easier to measure other points along the pond's perimeter. It is almost always better to add soil and bring up the low sides. Add soil as needed while making sure to use a tamper to compact the new soil so the pond does not shift or sink, creating a possible leak. Bringing up the lower sides also will prevent runoff water from rains and irrigation from entering the pond with dirt, fertilizer, other chemicals and/or debris.

STEP 3 Diggin' Pre-formed Ponds

Now that we have taken into consideration all the possible locations, decided on the best scenario and viewing angles and then leveled the pond area, it's time to put this pond in the ground.

Place the pond right side up and positioned how you want it to be when completed. Spray-paint the perimeter of the smallest (deepest) area of the pond onto the ground and dig that area to a few inches past its length. Insert the pond into the hole and dig deeper if necessary until the plant shelf area of the pond lies flush with the ground. Now repeat the spray-painting, but this time trace on the ground the shelf area of the pond.

Before you start to dig again, take the measurements from the pond's edge to the pond's bottom and from the pond's edge to the pond's plant shelf area. Dig the complete spray-painted area to the depth of the measurement taken from the pond's edge to the pond's plant shelf.

As you dig, remember to stretch the line-level intermittently from one side of the pond to the other and tie both sides to a screwdriver. By doing this, you can measure from the stretched line to the excavated area and obtain an accurate measurement of the depth. Repeat the digging and measuring process for the deepest part of the pond.

Once you completely dig the pond and the pre-formed pond liner fits nice and snug, measure one more time with the level to make sure that the pond is even. If it is off, add some soil on the lower side, and compact with the tamper. Do this as many times as necessary in order to get the pond completely level.

STEP 4 Adding a Waterfall Filter Unit

One of the biggest mistakes I see quite often in waterfall installations is the scale ratio of the waterfall height to the pond size. Too large of a waterfall is difficult to make aesthetically believable and natural-looking. The splashing from oversized waterfalls also makes it difficult to see the fish. To install a taller or larger waterfall into a small pond, place the waterfall a few feet away from the pond's edge or, preferably, at the end of a 7- to 10-foot stream.

I prefer to position the waterfall unit so you can see it at a 45-degree angle from the preferred viewing area. By positioning the waterfall in this manner, you will see more of a three-dimensional water movement splashing from rock to rock as it makes its way down the falls and forward into the pond. If you position the unit facing the preferred viewing area directly, you see the water only as it travels down the waterfalls, not down and forward.

After positioning the waterfall unit, make sure that the area that the unit will sit on is level. Use a torpedo level, and either add soil or remove soil as needed to level the area. Now attach the plumbing to the waterfall unit.

To provide a higher flow volume, we will use 1½"-inch Flex-PVC for the plumbing. Doing so will reduce the use of 90- and 45-degree fittings that rob the pump of its maximum flow rate at the waterfall's spillway. Some units need PVC primer and glue to attach, while others use a "worm'' clamp. If PVC primer and glue is required, always use the primer regardless of how clean the pipe might appear.

Our waterfall unit requires PVC primer and glue, so apply the primer to the 2 inches at the end of the PVC pipe and to the PVC fitting. Allow them to dry for 30 seconds or so. Once dried, apply the PVC glue to the primed areas, insert the PVC pipe into the PVC fitting, and allow it to dry for a few minutes.

Place the waterfall unit in the leveled area, and place soil around the unit except on its front face. (NOTE: Make sure, when placing the soil around the waterfall unit, not to disturb its level. Check the level often, if needed, by placing the level on the front-top edge and side-top edge of the unit.)

Carefully tamp or compact the soil as you add it to prevent future settling that could cause your waterfall to develop a leak. I have found through the years that 95 percent of all pond leaks are located within the waterfalls. Create a slope around the waterfalls that will give a gradual and natural appearance that will be easy to landscape when the project is completed.

To prevent the water from coming out of the waterfalls and spilling into the ground, we need to install a piece of 45 mil EPDM liner onto and from the waterfall unit into the pond.

This step is very important, and attention to detail is a must.

First, cut a piece of liner long enough to stretch from 1 foot inside the pond's edge to 2 feet past the waterfall unit. Place one end inside the pond, and secure in place by setting a large stone on top of the liner. Now lay the liner toward the waterfall unit, draping the excess over the unit.

With PVC primer, clean the liner and the waterfall unit's area where the liner will be attached. Remove any wrinkles on the liner, and place it against the waterfall unit.

Now place the liner attachment plate on top of the liner as close as possible to aligning the holes on the plate and the waterfall unit. With either an awl or a small Phillips screwdriver, start with the outermost hole and feel around until you can punch through the liner and waterfall unit. Carefully remove the screwdriver without moving the aligned plate, insert one of the provided bolts, and loosely tighten only a few turns. Repeat this step on the opposite side's outermost hole, insert a bolt, and tighten loosely.

Most waterfall filtration units include a tube of silicone for the next step. If yours does not, your local hardware store will have plenty. Silicone has different grades and colors; I prefer black and No. 7 on the adhesion scale. Open your silicone, and have it ready close by if you are doing this by yourself for the first time.

Carefully loosen the two bolts from the waterfall unit while keeping the liner and plate on the bolt. Next, place the plate, liner and attached bolts on your lap, and apply a very generous silicone bead on the waterfall unit. The silicone creates a watertight seal between the liner and the waterfall unit. Do not apply the silicone between the plate and the liner.

Once you apply the silicone to the waterfall unit, using the bolts that are attached to the plate and liner as guides, screw the bolts into their respective holes on the waterfall unit. Tighten the two bolts until the plate makes contact with the waterfall unit, but do not tighten completely.

With the awl or Phillips screwdriver, punch through all the remaining holes, and install the remaining bolts loosely. To complete the plate and liner installation onto the waterfall unit, tighten all the bolts starting in the center and working your way out to both sides. Do not cut off the excess liner yet; this will be done in a later step in the project. That was the hardest technical part. You’re almost done – great job!

STEP 5 Time to Rock

With the waterfall unit attached to the liner, it is now time for the artistic part of the project: creating the rock waterfalls. The beautiful thing about waterfalls is that as long as they don’t leak, there is no right or wrong. Beauty is in the eye of the beholder.

Another good point is that we are going to dry-stack the waterfalls without using concrete. If you don’t like what you get, tear them down and stack them again.

Start by placing stones on the shelf inside the pond just in front of the waterfall unit. For smaller waterfalls such as this one, I like using varying stone sizes that range from football size to watermelon size. The larger the better, as stones that are too small will look like a bunch of small rocks with water falling over them, which is not too natural. Try to be consistent with the alternation of sizes throughout the waterfall; do not put all the large stones at the bottom and the smaller ones on top, or vice versa.

Place the outermost edges of your waterfall slightly farther toward the pond than the waterfall’s spillway. This ensures that all the water that overflows from the waterfall unit remains within the linked area and won’t escape to create a leak. You might need to backfill some areas with soil once you turn on the falls.

STEP 6 Skimmer & Pump Installation

Once you're happy with the appearance of your waterfall, it is time to install the skimmer and pump. Always install the pump and skimmer on the opposite side of the pond as the waterfalls. This will allow for even flow and the complete filtration of the pond's water.

To choose the correct pump size, I like to use a minimum of 100 gallons per hour for every inch of waterfall spillway. If the waterfall unit has a 12-inch spillway, then I would use a pump that can flow a minimum of 1,200 gallons per hour.

Attach the pump's intake side (suction side) to the skimmer, and place in the pond where it will be located. Dig a trench around the outside edge of the pond from near the location of the skimmer to the Flex-PVC that is attached to the waterfalls. Place the 1 ½-inch Flex-PVC into the trench, and cover with soil. Cut off excess pipe, and attach the end to the pump's return (discharge side).

All pumps have varying sizes for their intake and return ports, so you might need adapter PVC fittings to attach two different-size pieces. The PVC adapter fittings are available at any hardware store in the plumbing section.

STEP 7 Let There Be Light

For a dramatic evening effect, add a low-voltage transformer and a few underwater lights. You do not have to be an electrician to do this. Follow the manufacturer's instructions; it should take only a few minutes to install. Put one light at the bottom of the pond on the skimmer side facing toward the waterfalls and a second light just under the waterfalls, pointing up.

As the light breaks the surface of the pond water, the ripples from the waterfalls create moving shadows on the falls and the landscaping around them. Move the lights around in the evening to get the best effect. This motion of lights and shadows is guaranteed to evoke a "Wow!" out of you every evening.

STEP 8 Getting Edgy

While you start to fill the pond with water, address that unsightly black pond edge. The easiest way to hide the pond's edge slightly above groundlevel is with two or three stepped or stacked rows of slate (flat stones). Lay the first layer of slate around the pre-formed pond's edge where it butts up to the black edge.

The second layer should sit on both the top of the pre-formed pond's edge and the first layer of slate as a "cap" stone. If this is not the case, then repeat the previous step, making it a two-stone layer on the side of the pond’s edge with the third being the “cap” stone covering the top of the pre-formed pond’s edge.

STEP 9 Let the Natural Melody Begin

By now, the pond should be full of water, so we’re almost ready to fire up the waterfall. Only trim the excess liner that is at the waterfall unit’s spillway; do not trim the rest of the excess, in case you find a leak.

Plug your pump’s cord directly into an exterior ground fault interrupt outlet. Do not use an extension cord, and make sure that the outlet has a cover that will protect the cord and outlet from the weather.

The last step is to check for leaks. Most can be fixed easily by backfilling with soil behind the liner in the area that leaks. Once you feel confident that there are no leaks, trim excess liner. If you see that too much water winds up behind the waterfall rocks and the waterfall’s flow seems “wimpy,” you might have to use waterfall foam in certain areas to “guide” the water to the front of the waterfall rocks. Spray expanding waterfall foam in areas that allow the water to disappear behind the waterfall. Allow it to dry for 30 minutes, trim off the excess, and plug in the pump to see what happens.

Waterfall foam is not intended to seal a leak. Adding waterfall foam in the wrong place might create a leak. If this occurs, remove the waterfall foam when dry, and reapply where and as needed.

STEP 10 Create Your Own Paradise Retreat

Now it’s time to turn this pond into your personal paradise retreat. Ponds and waterfalls are great all in themselves, but a beautifully landscaped pond and waterfalls are awe-inspiring. To create a natural and tropical-looking landscape around water features, I create a design style I call “Careless Abandon.”

As the name suggests, the design is simple and low-maintenance. I use plants that will grow and crawl into each other and require trimming only once a year. I like to use different varieties of ferns and jasmines that will grow and crawl over the pond and waterfall and “soften” the edges.

Add a few palms here and there with a splash of color via Hawaiian ti, heliconia and voila. Your local garden center can help you choose the plants that will work for your individual taste and climate. Keep the plants low-maintenance so that you can spend most of the time enjoying your pond. Match the ease of this construction with an easy-care water garden.

Freddie Combas “The Pondman”™ is president of Florida Water Gardens Inc. and a founding member and advisor of the board of the International Professional Pond Contractors Association. Ponds Magazine – Summer 2007