What Causes Foam In a Waterfall and Their Fixes


Last week I was taking a stroll along my sister’s water garden, and happened to notice that while her water lilies seemed to be blooming near the edges, the little waterfall she had set up was foaming a lot, and the foam seemed to be spreading and accumulating in the pond too. This did not look right, and upon researching, I found that it indeed was not.

So, what causes foam in a waterfall and how can one fix it? The accumulation and spread of foam from a waterfall can be caused by imbalance of nutrients, overpopulation of fish, or the filter’s inability to get rid of waste. Adjusting or changing the filter, reducing fish population etc, can help.

Normally, it is natural for fountains, waterfalls and any other swiftly moving water bodies to foam at the region they hit the surface of the pond they are part of. However, it is an indicator of issues in the water garden if the foam does not ever seem to die down, and instead spreads like a thick layer gradually over the water’s surface. There can be several reasons behind this foam layer, which is white and exists in a layer distinct to the pond’s surface. It would be such a horrible thing for any pond owner or gardening enthusiast to find their beloved natural region so tainted.

This white foam can look very unsightly and can also be harmful for the health of your aquatic plants and fish in the pond. This foam, when it spreads too far across the surface, can prevent air from passing through and this can negatively affect the entire ecosystem. Thankfully, there are means to remedy it, other than using anti-foam solutions available online and in the market. When you first spot the foam in a waterfall or fountain, it is best to observe if it is lingering and beginning to spread, and then tackle the situation quickly before it spreads too far. Sometimes, if one is watchful and knows what signs to look out for, foaming of this sort can be prevented beforehand. If not, there are still ways in which the problem can be resolved, depending on the nature and cause of the foam.

Causes for foam in a waterfall, and how to fix it

  • Sometimes, excess sunlight is a cause for the formation of foam and subsequent stagnation of the same in the pond. When the waterfall is situated directly under sunlight, and the sunlight is pretty harsh, the rate of evaporation becomes high and thus, the amount of substances such as waste released in the flow increases and coagulates in the form of foam. In a home grown water garden, it is quite possible to move the waterfall out of direct sunlight and place it in a more shaded area.
  • The kind of water used in the pond as well as in the waterfall is important. If you use water that is basically untreated and not distilled, it could end up producing way too much waste and thus, foam could accumulate. Moreover, if you don’t change the water regularly, every two to three weeks or so, this can also cause foam in the waterfall. It is advised to use distilled water as much as possible for both the pond and waterfall, and to change the water regularly to avoid foam.
  • While regular water change is important and necessary for the health of the pond and waterfall, sometimes part of the process ends up causing situations that build up foam as well. For example, using a dechlorinator to clean up the water you’re putting in your pond, may add more chemicals and change the balance of the pond and the waterfall, thus causing foam. A good idea is to use a water purifier system, many of which are available online these days. What these do is aid in filtering water and adding it to the pond as and when water changes occur. This keeps the waterfall and pond fresh as well as clean.
  • High levels of nitrate in the waterfall and pond can cause accumulation of foam. The presence of high content in nitrate can indicate either a vast gap between water changes, or overpopulation of fish in the pond. If the latter is what is happening, you will find that not only is the waterfall suffering aesthetically due to the foam, the fish are also affected and may even die if left unchecked. You can consider reducing the population of fish to fix the situation, or can create a different section of pond where you shift a fraction of the fish.
  • Sometimes, it so happens that the rocks or stones, or other features of the built waterfall are not cleaned regularly and thus there is accumulation of dirt and waste. This can lead to build-up of foam. Regular cleaning of the waterfall is just as important to avoid build-up of foam. It is a good practice to use a scrub brush and regular dish washing liquid to clean the stones and fixtures around the waterfall. These stones or rocks must then be hosed down a few times with clean water, thoroughly, before placing them back in the waterfall region.
  • For water stains and magnesium or calcium deposits, use chlorine bleach but do not leave it on the surface for more than a few minutes. Leftover chlorine can ruin the quality of the waterfall fixtures, damage water pH balance, and can also cause additional accumulation of foam.
  • Another cause for foam in a waterfall is the inability of the filter to clean the water properly and thus, failure to adequately get rid of toxins and waste. It could be that the filter is not functioning properly or that it is too small for the entire area of the pond. If the filter is too small, you will know this as some parts of the pond will be cleaner than others. The solution is to either install a larger filter, or use more than one, situating them in different parts of the pond, depending on its size and depth. You could use one filter specifically for the waterfall, for best results, and to avoid accumulation of foam.
  • If concrete is one of the materials used in your waterfall fixture, be sure to clean that regularly as well, since over time particles can come loose and clog up the water, creating foam. Regular soap will not work properly on cleaning concrete parts, so scrub the parts with three parts white vinegar mixed with one part water. This will remove the foam that has collected, as well as any slime and other grunge.
  • Sometimes you may need to add some sort of medication to the waterfall to fix other potential or existing dangers to the waterfall’s health. While it can fix the issue at hand, this medication can block the surface of the waterfall and create foam, making it difficult for oxygen to pass through. It is advisable to keep the aerator on while you are adding the medication, or to use a simple pump if not a full aerator system, to avoid foaming.
  • Many people resort to using a protein skimmer in order to avoid buildup of protein and hence avoiding foaming in the waterfall and pond. However, the protein skimmer has a tendency to drag forth protein particles by the use of bubbles, and this excess foam is generally gotten rid of by the disposal hose. In some cases, the disposal hose can become clogged or may simply stop working, and that can lead to even more accumulation of foam in the waterfall and pond. Ensure that the hose is cleaned regularly, just like all other parts of the maintenance system, aerator, etc, to avoid this recurrent foam issue.
  • An imbalance in the nutrients in your pond could be one of the biggest causes for foam in the pond and waterfall. Test kits are easily available, with which you can check the chemical balance in your pond and waterfall, and see if it is high in nitrates and/or ammonia, and low on oxygen. These conditions could lead to further building of waste particles on the surface and cause relentless foaming. To fix this, there are a few simple things that can be done. If it is a simple matter of low oxygen levels, a high-powered oxygenator would do well to restore the adequate levels of oxygen and eliminate foam. Hornwort is a lovely aquatic plant you can use to oxygenate the pond. However, if it is a matter of ammonia and nitrates, you can plant hyacinths, water lettuce and canna to bring a balance in nutrients and naturally reduce the presence of foam to the point of non-existence.
  • If you have many fish in your pond, and perhaps frogs or toads as well, their spawning could be a reason for foam in the waterfall and pond. It so happens sometimes, that people position water lettuce and such leafy plants near waterfalls to increase the aesthetic appeal, and this also provides excellent breeding ground for frogs. Excess spawning can lead to release of protein in the water and can cause foaming, and there is not much you can do about this other than moving the water lettuce to a more contained area, such as a net basket away from the waterfall.  
  • Adding to the point above, overfeeding or feeding the inappropriate type of food to the fish in the pond can also lead to foam creation in the pond and waterfall. In case of foaming due to waste created by overfeeding, you may not even realize you have been overfeeding, since the fish will eat it all in one go. But the more they eat at one point, the faster they will release more waste as well, which is most often in the form of protein. The key is to feed the fish for about five minutes at a time, a few times a day, so that they remain full but don’t overeat. In autumn and winter months, stick to wheat-germ based low protein foods for your fish to avoid them releasing protein in the water and creating foam.  
  • Another common cause for accumulation of foam in waterfalls is lack of proper aeration. Ponds in general as well as fountains and waterfalls that are part of its manmade ecosystem require adequate and proper aeration to function well and keep healthy. When the aerator is not working, is not powerful enough for the whole area, or is simply unable to cater to the needs of the pond, waste accumulates and air is unable to pass through the surface. Thus, foam tends to accumulate. The solution here is simple- make sure the aerator is running properly and undergoes regular cleaning and maintenance. Before purchasing the aerator(s), ensure that the power, capacity, etc. is perfect for your pond and waterfall. If necessary, get a smaller aerator for the waterfall separately.
  • Run-off into the water and lack of proper flow can also be a reason for foam accumulation. All you can do in this case is check the functioning of the waterfall and repair it or get it fixed by specialists after gauging the root of the problem. Sometimes there could be some blockage in the path or where the water flows from, which leads to stagnancy and foam creation in the waterfall. Further, in hotter season, it could happen that the water level gets lowered, and hence the flow is affected- and in turn, foam is caused.

Tips to take care of a waterfall in a home pond or garden

Waterfalls are lovely, picturesque fixtures in any aquatic garden or pond. They add instant grace and beauty to the pond and emulate a more natural surrounding as well. However, as seen above, problems like foaming due to imbalance of nutrients, overfeeding fish, etc. can make waterfall maintenance a difficult task and may be rather daunting to a prospective gardener who wants a waterfall or fountain. So here are some tips one can keep in mind with regards to choosing and keeping a waterfall in their garden or pond-

  • If your waterfall is situated directly or even near about under the shade of trees, chances are that particularly pre-autumn and during the season itself, lots of leaves will fall on the waterfall. Hence, to protect the waterfall and prevent the leaves from accumulating and creating foam, it is a good practice to cover the waterfall with a pond net that would catch the leaves. You can then clear the debris every day.
  • Remember that the waterfall remains the most efficient and functional when running constantly. Switching the pump on and off will just disrupt the smooth flow rather than conserving power or anything like that. It is also important to ensure that the pump and if applicable, light(s), is/are kept under water to keep them from overheating.
  • Water level is rather important for the proper functioning of the waterfall, which, in home gardens and man-managed ponds, is often a stand-alone feature. It happens rarely, but low water level can also cause accumulation of foam and look unpleasant as well. Always ensure that there is enough water running in the pump.
  • Always ensure that the waterfall you are setting up was meant for that very purpose. If it is an indoor waterfall, do not use it outdoors as it may catch fire due to electrical short-circuiting as the parts are not designed for withstanding outside elements. Similarly, outdoor waterfalls are often created to have aesthetic and dramatic effect by splashing and the like, and this can be unsuitable indoors.
  • If you’re carving your waterfall out from scratch, ensure that the rocks and stones you use for it are settled in or glued in properly to avoid them tumbling down and ruining your hard work. If you pile them high enough to make a tall wall, this problem should not occur and the waterfall should be perfect.
  • It is not necessary, but still good to know the various parts of the equipment used to maintain the waterfall and pond. The skimmer, for instance, has a debris basket, a filter mat and a pump, and knowing the distinct functions of these will help you understand what’s going wrong if it stops functioning.

Related Questions

How are waterfalls beneficial to us when maintained in home ponds, gardens or indoors?

Waterfalls are known to be stress-relievers as the soft splashing and murmuring of water is soothing to the senses. Waterfalls also make for great fengshui objects- flowing water is equal to positive chi and hence, balance. In addition, waterfalls can purify the air to some extent.

What are some beautiful and easily installed pond fixtures/ designs other than waterfalls?

To create a unique backyard pond, you can use fountains, pool lights and fairy lights as well. However, truly different ideas are to design the ponds by using already available items- say a hot tub, stone and bricks you can paint, tires, colorful pebbles and even mirrors.

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