In a world where budgets have become increasingly tight and there is too much to do most days, maintenance on your pond seems like just an extra time consuming expense.
But preventative maintenance will stretch your dollar farther and will reward you with less problems each successive year. The other advantage is that maintenance can be done on a more flexible schedule than treating outbreaks. The key to all this is finding the right place to use your maintenance dollar.
The best place to start when deciding on a maintenance program, ironically, is in the past. When you think back to the last few years, what problems did you have that you want to prevent? These are different for each pond, but just as symptoms help your doctor diagnose your illness, problems in your pond can point towards the cause.
Below, I will explore some of the most common problems and the maintenance program that will best help solve these problems before they start.
Algae Blooms: An algae bloom is when the algae population in the pond explodes as a result of ideal conditions. Algae blooms are algae suspended in the water column and can be green, brown, yellow or even red.
Essentially, algae require light, nutrients and the right water conditions to grow. If these are not all present then algae will not flourish and grow out of control. Since algae blooms are generally close to the surface, light is plentiful and hard to block. So there is not an effective way to prevent your bloom this way.
However, nutrients are provided to the algae as soluble nitrogen and phosphorus stemming from fertilizer, fish waste and decomposing plant matter and can be diminished with the use of beneficial bacteria. These bacteria require oxygen to work effectively and compete with the algae for the same nutrients, and as such will limit algae growth. It takes a few treatments for the bacteria to tie up the nutrients so it is important to start before you have a problem.
Water conditions in a pond can be manipulated using pumps and aeration. By using a pump or an aeration system to circulate the water (top to bottom and side to side), you can achieve conditions that are unfavourable to suspended algae.
Most suspended algae like to stay near the surface where there is lots of light, and many types also prefer still waters so that they do not move around as much and risk being damaged. Creating an environment less suitable to suspended algae will slow growth, or prevent algae from establishing.
Excessive Weed Growth and Algae Mats: Excessive weed growth and algae mats in your pond often indicate a rich source of nutrients on the bottom of the pond. These nutrients take the form of a bottom sludge layer that looks unattractive in its own right.
Weeds and algae mats, just like algae blooms, require light, nutrients and the right water conditions to grow. By disturbing one or many of these conditions weed problems will improve.
To reduce light in the pond for weed and algae mats that often start on the bottom of the pond, you can apply pond dye (commonly available in either blue or black). Pond dye increases the reflective nature of the water and decreases how much light makes it to the bottom where the plants and algae need it to start growing.
This is most effective in areas of the pond deeper than six feet and when applied very early in the spring. This dye has the added benefit of being safe to use during irrigation as it is simply a dye and not a pesticide.
To reduce the nutrient base for rooted weeds and algae mats, sludge-targeting beneficial bacteria can be used in the presence of bottom aeration (air stones or diffusers) to accelerate the breakdown of nitrogen and phosphorus.
As the bacteria break down the nutrient source there is less available for the weeds and algae to survive on. Most of these bacteria require the presence of a good oxygen source to work well. Therefore, applying them without aeration will not give the desired results and can lead to frustration.
Without aeration these beneficial bacteria may be a waste of your budget as they will not thrive. Plants and weeds tend to be less susceptible to water conditions in general, so water movement (more or less) does not have the preventative effects on them as it would on an algae bloom.
Cloudy water: Cloudy water can be a frustrating problem for people as it can be caused by many different problems that all show up as a single symptom. Just as a fever can be associated with many illnesses, cloudy water can occur because of several causes. Cloudy water is generally either suspended clay and sediment particles or suspended algae that may be alive or dead.
Suspended clay and sediment can cause cloudy water on a continual basis or periodically (such as after heavy rains), but regardless, there is always something that is causing the particles to be suspended.
Some common causes for particle suspension are runoff into the pond directly or into the river upstream, fish (such as goldfish or carp) and wildlife digging in the bottom sediment for food, or excessive water movement in the pond made by waves, fountains or aerators.
The first problem of runoff stirring up sediment can be mitigated by adding a buffer zone around the pond that allows the water to slow down and drop out any earth particles it is carrying, and enter the pond more slowly to prevent bank erosion.
Buffer zones can be a naturalized area, rock bed or even a flatter area of land. You can also use emergent water plants such as water iris, cattails and reeds to stabilize the shore and prevent erosion if a buffer zone is not possible.
Suspended algae are probably the most common cause of persistent cloudy water even though it is generally not suspected. If none of the situations above seem to apply to you and you often start out the year with a nice clear pond that becomes cloudy as summer progresses, you may have suspended algae in the pond.
The easiest way to be sure is to look at your water under a microscope. Live suspended algae can be prevented just as an algae bloom would be treated. One of the big challenges is dealing with algae that are already dead.
Dead algae can occur from natural die off or due to a treatment of algaecide within the pond. Algae, like all living things, are made up of cells and even after dead these cells still exist in the system.
When the algae are dead they often have very little colour and float freely, but just the presence of the multitude of cells can make it hard to see through the water. The best way to clarify water of dead algae is to degrade the algae at an accelerated rate and settle the algae out of suspension.
This can be done using a combination of micro-floc, created by beneficial bacteria, and periodic reduction of water movement. The micro-floc created by specific beneficial bacteria will clump the dead algae together causing the mass to increase in weight and making it more likely to sink, while the bacteria breaks down the cell wall more rapidly than it would naturally occur.
Shutting off aeration or other causes of mixing during the day, paired with this beneficial bacteria, will allow these heavier groups of cells to settle, often achieving clarity.
With some planning in advance you can avoid the use of costly chemical treatment and time consuming manual treatment. I hope that this knowledge will help you to choose the right preventative maintenance program for your ponds and stretch your pond budget further.
If you have problems not discussed here, or need help finding the right product for your pond, we would be happy to help.
By Julia Webber
B.Sc. Marine and Freshwater Biology
Fish Farm Supply Co
Aquaculture & Pond Supplies
