Written by James F. Burns
Water coloring for weed and algae prevention
In order to prevent the growth of weeds and string algae, water in almost any type of pond or lake should not be perfectly clear. The way the water is colored is of major importance.
Clear water will not stay clear very long when exposed to the sun. Something will grow in the water, and it will probably not be what you want. To control this in farm ponds, fish ponds, lakes, or even in koi ponds and other backyard ponds, you will have to take some action. Prevention is better than trying to treat for slime, blanket weed, or submersed lake weeds later on. Getting out in front on this issue could save you a lot of money in treatment costs.
Pond water color good and bad
Not all pond water color is good. Turbid or muddy water isn’t good for any beneficial aquatic life, and the problem causing the turbidity should be solved before anything else can be done to improve water quality. This problem can occur for a variety of reasons, the most common of which is a bare watershed. Once the cause is dealt with, the water can be cleared using a flocking compound, and then the real work of getting the water properly tinted can begin.
The best pond water color is achieved with algae. Not string algae or pond scum, but the type of algae suspended in the water, known as phytoplankton.
Phytoplankton for pond water color
Phytoplankton is the best solution to most water clarity issues, it shades the water against sunlight, and uses nutrients which would otherwise be used by weeds and string algae, and it feeds zooplankton which feeds fish. There are several different types of phytoplankton.
The type of phytoplankton present in the water is also important. There are many types, but perhaps the most productive is diatom plankton. These are the microscopic plants with silica exoskeletons which exist both in salt water and fresh water. Like phytoplankton in general, their numbers are diminishing, and have been for many years. Diatoms are very efficient in food production, and present a marked increase in zooplankton when they are present in large enough quantities. Diatom algae adds a golden brown tint to pond water.
Green phytoplankton, have cellulose as their skeletons and produce increases zooplankton, but to a lesser degree than diatoms. Both produce color in the water, both remove excessive nutrients from the water, both produce oxygen, break down carbon dioxide, and raise dissolved oxygen levels, and both reduce weed and string algae production. Diatoms produce these desirable effects more efficiently, and great strides forward have been made in efficient means of producing it. Green phytoplankton produces similar results, but phosphorous is needed to produce and maintain this bloom, and phosphorus supplies are running low. Not all green algae are the same.
Dyes for pond water color
There are occasions where phytoplankton production may be difficult to acheive due to a variety of factors such as local water use restrictions. It is even possible to produce some types of fish without the presence of high concentrations of phytoplankton. Catfish respond well to regular feeding, and the introduction of fathead minnows into the environment, but for weed control, and for temperature control, some coloring of the water is needed. In such situations, and for decorative fish ponds, fountains, and other decorative garden type ponds, dyes may present the best possible alternative.
Written by James Burns
The relationship between pond algae and water clarity can seem a little confusing for a pond owner. Clear water is not always good water, and one type of pond algae is the best prevention method for undesirable pond algae. There are many types of pond algae, some desirable, and some not.
If pond algae, of the pond scum or blanket weed type is forming a dense mat on your pond or small lake, there is about a 98% chance that the water beneath the mat is crystal clear. Check it out, and then come back, and I will tell you how I know this.
Back so soon?
It was clear wasn’t it? How do I know? Simple. Pond algae needs sunlight to grow. Pond algae needs soil to grow. For sunlight to reach the bottom of your pond, where pond algae gets it start in life, the water has to be clear. As the pond algae grows, some of the oxygen it produces by photosynthesis is deposited on the bottom of the mat of forming pond scum, and gives it the buoyancy to rise to the top of the pond. Submersed pond weeds, and blanket weed pond algae need clear water to produce, and in spite of all the thousands of products on the market that tout the virtues of clear water, and why their product will produce clear water, clear water is not desirable in a pond or lake where fish are producing.
Types of unclear water
Let’s make a distinction between types of unclear water. Do not confuse muddy or turbid water with the properly green colored water produced in a healthy pond or lake. Muddy water is not healthy water. In fact, water containing suspended soil particles is bad for the fish population. It is an irritant to fish, which causes them to feed less, fidget more, and often lose weight. It also prevents the natural photosynthesis process needed for the food chain. No, the water color needed for a healthy fish pond has a green tint, that will prevent sunlight from reaching more than 18 to 24 inches below the surface. There are products on the market that will color the water to prevent sunlight from reaching the bottom, but they have the same issue that makes muddy water undesirable. They suspend the food chain activity. So what is this magic color that prevents sunlight and provides the beginning of the food cycle?
Phytoplankton is a single cell algae that becomes suspended in lake and pond water, and is important for what it produces and what it prevents.
Phytoplankton produces oxygen through photosynthesis which becomes available to aquatic life. Without oxygen in the water, your fish will die.
Shade and cooling
The phytoplankton type of pond algae provides shade for the water which helps to keep it cool. This is very important in the hotter parts of our country during the summer months.
- Phytoplankton is the food source for the tiny creatures known as zoo-plankton
- Zoo-plankton becomes food for insects
- Insects become food for small fish
- Small fish become food for large fish
- Large fish become food for you.
Weed and pond algae prevention
The tinting effect of phytoplankton prevents sunlight from reaching the pond bottom, which prevents pond algae and submersed weed problems.
So, how can you produce this miracle pond product? First: If you have a heavy cover of lake weeds or pond algae, get rid of it.
Check the water color.
You can do this with a tin foil pie pan nailed to the end of a stick, although a more accurate measure can be attained using a “secchi disk” designed specially for this. Either way, if you can see the disk or pan at a depth greater than 18 to 24 inches, your pond is too clear to be healthy.
Test the waters pH
You can do this with a swimming pool test kit that you can purchase at most places that sell pool supplies. If the pH is between 8.6 and 6.8 you can go on to the next step. If it is lower than 6.8, the acidity is too high and will need to be changed before the next step. Agricultural limestone will correct the problem. I ton of agricultural limestone on one surface acre of water will raise the pH by 1 point on average. If you have a 1 acre pond, and the pH is 4.8, you will need at least 2 tons of limestone to bring your pond up to the minimum pH needed for healthy aquatic life. Do this before taking the next step.
Fertilize your pond
Fertilization will produce algae bloom, or phytoplankton in your pond. The right fertilizer is a fertilizer high in phosphorous and low in the other 2 elements. Phosphorous is the middle number in the 3 numbers listed on a bag of fertilizer. You need to add 40 lbs of 20% phosphorous, or 20 lbs of 40% phosphorous, or something similar in ratio per acre to initiate algae bloom. See also: How To Fertilize A Pond Or Lake