Professional Service & Products

Water Garden Review for the Not-So-Dumb

Books for Dummies? You aren’t that Dumb, So let’s dig deeper...

Water gardens are a fantastic and dynamic addition to the landscape.  Nothing will attract attention in the landscape like moving water, the lush and unique nature of water plants, as well as koi and goldfish gracefully swimming and meeting you at the pond edge to beg for a little feed.  The hardscape of a pond, whether formal or natural design lends itself to additional landscaping to frame up your yard into a beautiful oasis. Water gardens also are green. They use less water than the same amount of sodded lawn and can also incorporate rainwater capture.

Water Gardens have been around for centuries in different parts of the world and with local adaptations.  They have been popular in the United States as well, but after the 1990’s they exploded in popularity due to the internet which spread quality information to help solve common difficulties, and helped make problem solving supplies and equipment more readily available. Prior to this, physical catalogs, libraries, and local clubs were the only source of information for hobbyists. There was also the appearance of the skimmer and biofilter waterfall kits on the market along with a strong push in marketing by the suppliers to train landscapers to install them.  Landscapers have an eye for design and the labor teams to install them however, they do not always have the additional education to solve the problems or to service water gardens properly. The big push in marketing, and the swell in the economy, also resulted in many new pond owners that purchased them as an impulse. These pond owners were not hobbyists and later regretted the purchase, after being annoyed with maintenance and some failures with plants and fish. Another group of new pond owners resulted from home purchases and the pond that came with the purchase.  They may have new enthusiasm for pond ownership, but may be frustrated with some of the deferred maintenance, poor construction, or lack of information.

A properly operating water garden is a pleasure to have in your yard and it should lower your blood pressure not raise it, so let's get a little more education to increase our enjoyment...

Water Garden Construction

Water gardens are generally an excavated space lined with either cement or an EPDM rubber liner to contain the water.  The depth varies with shelving to accommodate getting in and out of the pond as well as to place plants at different depths.  Seldom are water gardens over 4 feet deep and most are 2.5 to 3 feet maximum depth. Koi ponds designed specifically for fish can be deeper, up to 10 feet, and seldom have shelves since plants are not a priority and shallow depths can provide a place for predatory birds to wade and harvest valuable fish.


These ponds typically are taking a traditional geometric shape that may reflect the area of a larger garden or courtyard. Many are raised above ground level to allow for sitting on the edge while you feed your fish.

Filtration equipment is incorporated in an adjacent construction that fits with the design, or is located remotely so as to not interfere with the view of the design.

Natural Waterfall

Popular skimmer/biofall systems have a large box skimmer on one side of the pond and an overflow waterfall box on the opposite side spilling into a constructed waterfall which may spill into the pond or into a stream prior to entering the pond.


The subject of fountains refers to two types of additions to a water feature: a statuary or bowl fixture spilling back into the main pond or a nozzle that water is forced through to squirt water through a fixture or into a pattern.  There are a few things to consider when thinking of adding this to your plan. Squirting water through a nozzle will generally take more pressure and smaller volume to make your display. This is in sharp contrast to what you will have in place for a waterfall pump or gravity flow biofilter if that is your overall design.  Also, apertures on nozzles will clog and need maintenance so choosing an effective prefilter for the pump will be important to avoid having a frustrating amount of maintenance to remove clogging. Keep in mind also that if your nozzle partially clogs, it may increase pressure on the remaining parts and shoot water out of your pond and drain it.  Bowl type fountains, whether a series or a single spilling type bowl, capture water and give it some waiting time before spilling it back into the pond. What is the result? Algae. When water with nutrients slows down, is given the opportunity to warm and be exposed to a greater amount of sunlight, then run in a relatively thin layer over the lip of a bowl it will grow algae.  Even ponds with effective filtration still have plenty of nutrients to grow algae and bowl fountains are a made-to-order algae culture machine. If you have a fountain of this type be prepared to clean algae off the surface and remove it from the bowl containers as a part of regular maintenance.

Containers/Special Containers

Smaller water gardens can be constructed from containers- whiskey barrels, sugar kettles, etc.  The smaller the water garden, the more maintenance is required and the more difficult it is to filter: filtration cost per gallon increases, and trying to fit it into the project is more difficult.


The water garden industry has developed a pump for almost any application.  Choosing the right pump, or pumps, for your application is not difficult with a little thought about what you want the pump to do for your project.  Waterfall? You will want to choose a high-flow, low-head (low pressure) pump. These pumps deliver great flow and are efficient, with a vortex type design that draws water through a large opening and an aggressive impeller to push water.  200 gallons per hour, per inch of waterfall width will generally give a ½ inch deep spill of water. This should be a minimum flow rate.

For fountains, a higher-pressure, lower-volume pump is generally a good choice.  Since the water will pass from the pump to the fountain, make sure that the pump is protected from pumping debris larger than the fountain will pass, or you will experience a frustrating level of clogging at the nozzle.

Filtration components


These are pre-pump filters.  Are they filtering the water in the traditional sense and improving the water quality?  No, but they are meant to keep clogging debris from accessing a pump, which would stop the circulation, aeration, and other filtration that the pump supplies.  Examples of this type of filter include a leaf basket paired with an on-shore type pump drawing in water and debris from a pond. Pump protectors/pump socks are popular and have a cylinder of filter matting containing the pump and a drawstring bag.  These are easy to clean, lightweight and perform well. New model high flow water garden pumps have an oval cage with perforations. These pumps also seem to work well as an in-pond pump without frequent clogging. Skimmers are another type of prefilter.


These are not small skimmers like you see in swimming pools.  These are large sunken boxes on the pond edge that are joined to the liner.  Typically, a submersible, high volume pump is located in the bottom of the skimmer underneath a horizontal layer of filter matting and the water entering the skimmer has to pass through a large capacity net frame (capturing leaves, grass clippings) and then through the filter mat prior to getting to the pump.

Mechanical filtration

Mechanical filtration is the actual capture and holding for removal of particles and debris as opposed to a prefilter, which is just an exclusion device in some cases.  This will require a second step of removing the material as a part of regular maintenance. Considering this step is important in the decision making when selecting a system.

Skimmers, as I mentioned earlier, are popular and do a great job of protecting the pump from debris, and they also capture floating debris and leaves.  Regular cleaning of the net on the inside of the skimmer is required. This involves kneeling beside the skimmer, removing the net and bracket, dumping the contents, rinsing it and placing it back in the skimmer.  This can be a daily maintenance chore, especially during the fall.

Pressurized canister type filters are compact and contain layers of filter matting or sponges to capture material.  They do a good job of capturing small particles that the pump can deliver, but when cleaning is needed the filter mats must be manually compressed and rinsed to remove debris.  This can be a messy process. This can less of a problem with more advanced designs that allow compressing and rinsing without opening the top.

Bead filters use floating polyethylene beads about 1/16th of an inch to form a floating matrix that the water passes through.  As water passes through the beads it captures fine materials down to 10 microns, especially after growing a nice layer of biofiltration bacteria, a second function.  After solids are captured, the beads are disturbed with water, air, or even a propeller. Then the solids sink and can be flushed out as a concentrated sludge. This process is not messy and can be done with just a couple of valves or switches.

If you choose not to have a mechanical filter, then you will have a buildup of debris and sludge in the pond.  This will be removed in the future with a complete cleanout. Cleanouts are usually a part of regular maintenance on water gardens but the necessary frequency of cleanouts will increase without a mechanical filter to remove some material.

Things to consider:

Mess of cleaning involved in maintenance.

Frequency of cleaning of the filter, and pond.

Load- amount of fish, feeding, and seasonal debris.

Water loss when removing sludge or maintaining filter.

Biological filtration

Biofiltration is utilizing bacteria to process the toxic ammonia produced by fish waste into nitrite and further into nitrate.  Ammonia is toxic. Nitrite is toxic and nitrate is not toxic to freshwater fish. So how do we culture and train our bacteria friends?  They are not free swimming, so they need a place to locate. Media is a material used to provide lots of surface area in a biofilter. The more suitable surface area, the more bacteria and the higher filtration capacity (the more fish you get to enjoy feeding!).  Some media that you will see on the market for biofiltration…

Filter matting- white matting also provides some mechanical filtration

Matalla matting- different densities in plastic rigid mats, also mechanical filtration depending on the density grade

Lava rock- cheap but leaches minerals and clogs over time.  Contained in mesh bag. Heavy and difficult to handle after established in a filter.

Strap media uncoiled strapping band material contained in a mesh bag.  Low clogging, high surface area, affordable and lightweight.

Bioballs- these have been on the market for years and while you can admire the design, they are just not that special with respect to volume to surface area and expense.  They are lightweight and durable.

Ribbed straw sections- This media is affordable, effective, and has a great surface area.  These are small cylinder sections with ribs and cross sections inside the cylinders giving the ½ pieces a huge amount of surface area.  These can be used in media bags, or in flow through biofilters. They work well in a fixed position to capture solids after they culture a nice coating of bacteria is established.

Bead media- is the ideal media and in addition to simple polyethylene beads, there is engineered bead media, with indentations increasing the surface area of the beads even further.  Bead filters were originally designed at LSU in the 90’s and continue to provide the ultimate in biofiltration, and mechanical filtration in a single small footprint filter. These filters are located out of the pond and are common on formal koi ponds as well as formal water gardens.  

Sand Filters

Sand filters have NO place on a water garden.  I have removed many of them. Please don’t waste your time or energy on anything besides hauling it to the curb for disposal.

Ultraviolet Filtration (UV)

Ultraviolet filtration sounds super technical but it is a common technology in water filtration and air filtration at municipal water production, hospitals, and in food service.  Ultraviolet light is produced from a special light bulb and irradiates water as it passes through the filter. Sized correctly and at the right flow rate (easy to determine) the UV filter will eliminate 99.99% of single-celled algae/phytoplankton, the source of green water.  This also helps with fish health as the filter will also eliminate bacteria, protozoans, viruses, and fungus that are in the water which reduces fish disease. Will this kill my bacteria in the biofilter? No. They are fixed to the media in the biofilter. The UV only contacts the water flowing through the UV filter.  A UV filter should be located, in general, after all other filtration to allow for the water to be free of debris and most effective.

The Fish

The most common species of fish for water gardens is koi.  Koi are a type of carp that have been selectively bred for over 1,000 years in Asia.  They are selected for body form, vibrancy of color, and color patterns. Long fin koi are and adaptation developed in the United States.  Japan is the source of the most advanced koi farms and breeding programs with generations of families involved in selecting and developing koi with pedigrees and specific traits. Japanese is   These koi can can reach incredible prices with the most expensive koi selling for over two million dollars. It is not uncommon in the United States to have koi over $20,000 among serious hobbyists. But a Stradivarius is not just any fiddle, and just because a koi is large, don’t start planning your retirement, just yet.  These koi have a genetic pedigree and are professionally selected for color and form.

If you are interested in koi there are affordable koi for the backyard hobbyist through water garden centers, aquarium stores, and local small farms, if you are fortunate enough to live near one.

Goldfish are another popular water garden fish and I personally prefer them in water gardens that are below 1,000 gallons.  They are a smaller fish than koi but can reach 8 inches commonly. Comets, and shubunkins are a great choice. Fantails and orandas are popular but probably better suited for aquariums. They are not fast swimmers and can be subject to getting pulled into high-flow skimmers or also more likely to get harvested by birds.  Goldfish will have lots of color and personality but since they don’t get as large they are better choices for the smaller water garden.

Water Quality

Fish need healthy water and they and their blood chemistry are in direct contact with the chemistry in the water.  Dissolved oxygen, ammonia, chlorine, pH, and temperature all affect your fish. These same chemicals affect the function of your biofilter and that affects your fish as well.  Does chemistry intimidate you and make you want to fill in your water garden? Don’t worry. Keep this simple. How?

  1. Treat your water with a readily available water treatment with dechlorinator.  This will remove chlorine and add some electrolytes for your water as well. Use more than the minimum label recommendation and keep enough to treat your whole pond on hand at all times.  This is a small investment and will protect your fish in the future if you need to add water. *Note: Forgetting to turn off the water when filling a pond is a major cause of killing koi in water gardens.

  2. Start slow.  Stock one or two fish and feed really conservatively.  One to two pellets per fish every other day. This will allow your biofilter to adjust and grow while protecting your fish. Don’t let your new excitement of owning fish get you into a situation that endangers your new pets.  Take it slow.

  3. Dissolved oxygen will mostly come from physically stirring the water which allows it to breathe.  Some oxygen will come from submersed plants and their photosynthesis...if you have submersed plants.  A good pump will provide adequate aeration. Use a pump and operate it 24/7. Some folks think that turning off a pump is an acceptable approach to energy savings.  No. If your fish live through the dip in oxygen, you will stress them. Your biofilter also needs oxygen and flow and will suffer if you turn off the pump for extended periods.

Also, an aeration system is an inexpensive investment and can protect your fish if the pump goes out, and also enhances your biofilter. It will cost pennies per day to operate.  An onshore compressor delivers air to a diffuser/airstone. The small bubbles produced by the diffuser add oxygen to the water and stir the water as they rise to the surface. If you have a small water garden without a waterfall or fountain, simply add an aerator to improve and protect your water quality.

Feed & Feeding

I remain surprised at the number of pond owners that do not feed a good diet to their fish- catfish food, cat food, cereal. If you have a pet of any kind, feed them a diet that is correct for them.  If you have koi or goldfish feed them a koi or goldfish diet so that they get proper nutrition.

Choose a floating pelleted food.  Flakes are designed for tiny aquarium fish and will pollute the water.  Floating pellets do not dissolve quickly and are easily identified by fish.  A high quality diet will be digested and used by the fish instead of passing into the water as waste and polluting the water making additional load for your filtration system.

Feed conservatively. Your fish should readily consume feed and it should all be consumed in less than 3 minutes.  Make sure that your feed is not having the opportunity to float in amongst the stone edging or into the skimmer. Rotten feed degrades water quality and cultures disease-causing organisms. Consider making a floating ring out of black poly pipe to contain floating feed until fish can consume it. If fish do not eat feed readily, scoop it out.  If fish are too cautious to feed they may be stressed from a parasite, poor water quality or stressful event like a predator or if they are newly added to the pond. STOP feeding for a few days. It is just degrading water quality. Let them recover and then feed a small amount to test when to return to a feeding schedule.

The Plants

Water Lilies

Water lilies are the decorative plant that we think of first when visualizing a water garden.  Round leaves, floating large blossoms shading the pond and creating a pattern over the pond surface.  The flowers smell similar to a gardenia.

There are two types of water lilies: hardy, and tropical.  

Hardy water lilies have a rubbery thick leaf with smooth edges. Flowers float directly on the water surface or possibly 1 inch above the surface, and are open during daylight hours.  These lilies will go dormant during the winter based on day length, and re-emerge in the spring. Long tubers hold lots of energy stores and can be easily divided to make additional plantings.  

Tropical water lilies have thinner leaves with serrated edges. Flowers are large and fragrant, and come in a wider variety of colors than hardy water lilies, including blue, purple, and deep pinks.  Tropicals also have night blooming varieties which can be a nice option if you have a day job and seldom are home to enjoy day blooming varieties.

Getting the most out of a water lily includes a few simple things:

Plant in a large ( 2-3 gallon), shallow ( no more than 10 inches tall), round container using clay based soil. Top the container with gravel to contain the soil.  Use large gravel if you have koi as they may try to root around in the soil and push it into the pond. Large gravel prevents this in most situations. If you want the most out of a lily, do not plant it in gravel, and certainly don’t leave it in the quart pot that it was purchased in at the store.

Fertilize with pelleted fertilizer tablets or slow release fertilizer wrapped in newspaper to make a small packet.  Place fertilizer deep in the post so that feeder roots can travel to it and fertilizer is leached into the clay based soil and not released in the pond.

Give it some room to grow.  The variety label may give you a size rating.  There are dwarf varieties for small water gardens and large varieties reaching up to 10 feet in diameter!  

Grooming you water lily will help its performance.  Trim off old water leaves and old blossoms by reaching under the water and pinching or cutting the stem near the base.  Removing old leaves and blossoms makes the plant healthier, look better, and stimulates new growth with more blossoms. Blossoms open and close over several days. How to tell if it is old or new and whether to remove it?  If a blossom is closed, squeeze it. If water comes out then the blossom has run its course and will not reopen. Remove it.


Anacharis is a submerged plant that can be planted in small water gardens.  Because of the inevitable maintenance associated with removing the overgrowth of submersed aquatic plants, and the general aggravation experienced by most of my clients, I only recommend them in small water gardens.  Plant a clump in a small mesh basket with gravel as the medium, and be prepared to give it a haircut. Also, since it is invasive in natural ponds, make sure that you dispose of it properly, avoiding a pond, lake, ditch, or storm drain.


Marginal water garden plants, in general, include those that grow in damp areas to six inches of water above the roots.  This includes irises, cannas, rushes, and low creeping plants. There are, literally, 750 varieties of Louisiana Iris and all are suitable for the water garden.  Longwood Cannas, Arrowhead, and Pickerel Rush are some of my favorites, and there are many more. Enjoy seeking out specimens to add to your water garden, but be careful.  It can be addictive. These can be planted in smaller pots with the clay based soil mentioned earlier for water lilies. Place them just below the water surface using a shelf, cinderblock, or inverted terra cotta pot for support at the correct level.  Some may be suitable for planting in a gravel pocket on the pond or stream edge. You can also use a mesh basket with gravel. Do not fertilize in gravel plantings. This is an “aquaponic” planting and the plant will draw nutrients from the water and dissolved organic waste. In larger quantities, these types of plantings can provide great polishing filtration for your water!

Everyone’s water garden experience is different.  It may be challenging at times, but it should be enjoyable.  With the general information above, you should be able to select the right components and have  areasonable approach to management to have a successful approach to water gardening. I hope that you have enjoyed digging a little deeper than a “book for dummies” approach, and I hope that you enjoy your water garden experience.