Pondkeeping Frequently Asked Questions

With pond season coming to an end, we have rounded up some frequently asked questions that we have received over the past year. Hopefully, the answers provided will clear up any questions you may have pondered.

What is the difference between LDPE and PVC pond liners?

LDPE and PVC pond liners are both flexible pond liners that are made from 2 different types of materials - polyvinyl chloride (PVC) and low-density polyethene (LDPE). The main differences are the levels of flexibility and the price range. In general, LDPE pond liners are more flexible as well as chemical and UV resistant. If you have a pond that is not a standard shape, LDPE pond liners will be great for you. LDPE pond liners are also great if you are on a budget as it is the most affordable option.

How do I calculate the amount of water in my pond?

When buying any pond product or pond fish, you will have to know how many litres of water your pond holds. If you are unsure, here is an easy way in which you can calculate it:

Measure the Length, Width and Depth of your pond in metres. If your pond is not a straightforward shape you will need to measure the average of all 3 sizes.

Which fish food is best to use?

The pond fish food that you use will depend on the type of fish you have in your pond and also the time of year. For koi carp, in the warmer spring and summer months, a high quality growth pellet is a popular choice. In the late autumn and winter, a premium winter wheatgerm food is essential. The wheatgerm food is easier for koi to digest and prepares their metabolism for the slowing down that occurs in the winter time. For more information about feeding koi in the winter, see our winter koi pond guide.

What is the best location in my garden to build a pond?

If you are thinking of building a new pond in your garden, you will want to consider the location as this will affect your enjoyment of it as well as the amount of maintenance that will be required. Try to avoid placing your garden pond in an area shaded by overhanging trees so that leaves will not fall into the water and cause poor quality water. If possible, choose a place that will get a mix of sunshine and shade so that pond plants will be able to bloom and algae will be less likely to become problematic.

How deep should my koi pond be?

Generally, a koi pond should be at least 3 feet deep. Five feet would be a more ideal depth – especially if you plan on keeping more than a few fish.

Do I need a pond heater in the winter?

Installing a pond heater is up to your own discretion. Depending on how cold it gets in the winter where you live, pond heaters are not necessary. Koi, goldfish and sturgeon are coldwater fish and can withstand freezing temperatures in the winter. As long as the pond water does not completely freeze, the fish will hibernate at the bottom of the pond where the water temperature is a bit warmer. In order to prevent pond water from freezing over, it is necessary to keep the water moving. Having a pond pump or air stone is a great way to make sure your pond water stays aerated and moving.

How often should I test my koi pond water?

Testing the water in your koi pond is very important as there are many factors in the environment that can negatively affect the biological balance of the water. In a new pond, it is recommended that you test your water once weekly. After 1-2 months of weekly water tests, this can be reduced to 1-2x monthly.

Will pond treatments affect the beneficial bacteria in my pond?

Many pond treatments today are made so that the chemicals will not negatively affect the beneficial bacteria that have built up in your pond. They are created to get rid of bad bacteria that can cause problems such as sludge, blanketweed, etc.  Just remember, it is important to follow the proper dosing instruction found on the packaging.  

Should I turn off my UV in the winter?

While the majority of you pond equipment can be kept on in the winter, your pond UV steriliser should actually be turned off and stored indoors. UV is not necessary in the winter due to the lack of growth occurring in the pond. Water inside the UV clarifier can freeze and expand which will damage the quartz sleeve, bulb, housing or electronics.

Tips to consider:

  • Pond salt is a koi pond keeper’s friend. Adding the right amount of pond salt to you pond will boost your koi carp’s natural defence system that fights stress and diseases. Salt is also a great way to get rid of any parasites that may be hanging about in your pond water.

  • If you do not have a pond pump or airstone running in your pond in the winter time, leave a tennis ball floating on the surface. The bobbing of the tennis ball will keep water moving just enough to keep the surface from completely freezing over – this ensures oxygen exchange between the air and water can still occur.

  • If you are not happy with using liquid pond treatments, barley straw is the old-school method of controlling algae. Simply stuff a bundle of barley straw in nylon stockings and tie the bundle to a rock/plant so that it will stay in the upper portion of the pond. If you have a fountain feature in your pond, place the barley sack nearby so that the moving water will help to spread the natural chemicals that the barley creates. Barley straw breaks down and releases a by-product that has been found to make water conditions unfavourable for algae growth while not affecting other aquatic life.