Commonly Asked Pond Questions

1. How large should my pond be?

The best advice is to build the largest pond that you can afford. Most people that install a small pond are always wishing it were bigger. Also, larger ponds are easier to maintain.

2. How deep should I make my pond?

It depends on several factors. If you only want a reflecting pond, 12 inches is fine. If you want a fish pond and/or water lilies then 18-24 inches is a good depth. If you plan on keeping large fish such as koi, an area 3 feet deep is usually recommended.

3. Where should I place my pond, and should I chose a sunny or shady location?

Most people think of a low spot in their yard but this is the worst place to put a pond. Low spots collect run-off which may include fertilizer, pesticides, and herbicides. You certainly don't want this in your pond and neither do your fish!


Ideally your pond should receive 4-6 hours of sunlight a day. Any less than this, and your lilies and other sun-loving plants will not bloom as much or at all. Remember also that trees can create problems by shedding leaves in the pond which decay.


The main recommendation is to put a pond in an area where you can enjoy it and where there is accessibility to water and electricity.

4. Should I build my pond above or below ground?

This is a matter of personal preference, ease of digging, and where you plan to place it in your landscape. Some prefer the look of a raised pond while others like an in-ground pond. Some even dig down part way and then take dirt and mound up around the sides. Above ground ponds can easily be constructed by using rocks, landscape timbers or railroad ties.

5. What are best, flexible or preformed pond liners?

Both work well and come with a 20 year life expectancy. Flexible liners usually look more natural and are usually more economical than preformed liners. Many people find flexible liners easier to install. Flexible liner is the only way to customize a pond's shape and depths. Harper's carries 45 mil EPDM rubber which is sold by the square foot.


Preformed liners are very sturdy and most come with built-in plant shelves. All preformed ponds are 18 inches deep. Preformed ponds work exceptionally well for raised flowerbeds. (The preformed liner will retain its shape without strong retaining walls needed to support flexible liner.)

6. What will be the cost?

The cost depends on the size of the pond you want to install and what features you are planning. A 2000 gallon pond with a waterfall will obviously cost more than a 50 gallon tub with a small fountain. Just ask and we will be glad to help you figure costs.

7. How do I measure for a flexible liner?

To determine the size of the liner, you must first decide the desired pond length, width and depth you want and then use the following formula for liner size:
Length in feet + (2 x depth in feet) + 2 foot overlap = liner length
Width in feet + (2 x depth in feet) + 2 foot overlap = liner width

8. How many gallons will the pond hold?

Use this formula to figure approximately how many gallons of water your pond holds: Average length in feet x average width in feet x average depth in feet x 7.5 = gallons

9. What about choosing a pump and filter?

You should circulate all of the water in your pond every 1-2 hours (and we recommend running your pump 24 hours a day.) For example, if you have a 500 gallon pond, your pump should be no smaller than 250 GPH (Gallons Per Hour). Many people make the mistake of getting a pump and/or filter that is too small for their pond. This results in problems, frustration, and additional maintenance.


To calculate a pump for a waterfall, you often circulate the water more frequently than every 1-2 hours to get the desired volume. Remember that a waterfall spreads water over a much wider area and therefore needs a larger pump. Waterfalls require 100 GPH for each inch of width. The height or lift from the pump to the top of the falls should also be considered. In addition, note the length of the connecting hose from the pump to the top of the water feature.


Filters aid tremendously in keeping your pond clear and should be selected to be compatible with your pump. A pond that is fully stocked with plants and under stocked with fish can sometimes be balanced without a filter. However, this is challenging to do, even for advanced water gardeners.

10. How do I keep my pond clear and free of algae?

Your pond should be a small, self-contained eco-system. Keeping your pond balanced requires that you have the following things in place:


Surface plants for shade. These plants offer essential shade for your pond and a hiding place for fish. Water lilies or other aquatic plants with leaves should cover 50-70% of the surface of your pond. This shades the pond, keeping the water cooler, and deprives algae of the sunlight and extra heat which it needs to flourish.


Submerged plants are essential. their purpose is threefold. They consume the excess nutrients in the pond, robbing algae of fertilizer. They offer protection and shelter for fish, and provide an excellent place for them to spawn. Also, submerged plants attract dirt, creating a natural filtration system.


Proper number of fish. We constantly run into customers who have overstocked their ponds with fish. This will easily throw the pond out of balance because the fish excrete more waste than the plants can consume. In stocking a new pond, the usual recommendation is for no more than one inch of fish per square foot of pondsurface area. Established ponds may have a maximum stocking level of 2-3 inches per square foot of pond surface area. It is important to closely monitor this.


Filtration and beneficial bacteria. We have found that in addition to the above suggestions, adequate filtration and the use of beneficial bacteria, an algacide or barley straw extract greatly help reduce algae problems.

11. What about electricity?

All of our pumps operate on 110v. Make sure that your outlets are equipped with a ground fault circuit interrupter (GFCI). This is a safety measure and is a must for an outlet near a pond.

12. During the winter, what happens to the fish and plants?

Fish store up fat during the fall and once the water temperature drops below 40 degrees the fish will stop eating. (Do not feed them once the water temperature is below 40.) During the winter, the fish go into 'hibernation' and move very little. They live under the ice and mostly spend their time near the bottom of the pond where the water is warmer. To keep gases from building to toxic levels under the ice we recommend adding an air pump and air stone or a deicer to keep a small area of your pond from freezing over.


Most of aquatic plants will survive the winter where they are in the pond. Unless the plant is borderline being hardy in our zone, there is no need to sink it to a deeper part of the pond. Tropical plants such as umbrella palms, water hyacinths, water lettuce and tropical lilies will not survive outdoors over the winter and should be removed before frost. Some of these plants you may bring indoors and treat as houseplants in a sunny location.

13. What should I do with my pump and filter over the winter?

There are many variables in winter pump use. Some items, such as external bio-filters, UV lights, and other fragile plastic pieces, cannot be kept outside during the winter and should be disconnected and stored indoors. Some people leave their pumps run all winter and others turn them off and bring them inside. (If left outside, all pumps and filters should be kept below the freeze level and the water level should be checked regularly since evaporation still occurs during winter months.) Because of the wide range of product specifications, the best advice is to ask a professional about your specific pump and filter.

14. How often should I clean my pond?

Regular maintenance should decrease the necessity of draining a pond . If a pond is netted before the leaves fall, properly filtered, beneficial bacteria is regularly added and cleaning with a vacuum each spring and fall a pond may never need to be completely drained.